# List of former United States senators

This is a complete list of all people who previously served in the United States Senate. As of March 2025, a total of 2,018 persons have served in the senate (including those currently serving).
In the party affiliation column, if a senator switched parties and served non-consecutive terms, their affiliation for each term is listed on the corresponding line. If one of these senators also served multiple non-consecutive terms with the same party, a quotation mark indicates that their affiliation did not change between that term and their preceding term.

## List of former senators

| Senator | Years | Class | State | Party | Lifespan |
| Joseph Carter Abbott | 1868–1871 | 2 | North Carolina | Republican | 1825–1881 |
| James Abdnor | 1981–1987 | 3 | South Dakota | Republican | 1923–2012 |
| Hazel Abel | 1954 | 2 | Nebraska | Republican | 1888–1966 |
| James Abourezk | 1973–1979 | 2 | South Dakota | Democratic | 1931–2023 |
| Spencer Abraham | 1995–2001 | 1 | Michigan | Republican | 1952–present |
| John Adair | 1805–1806 | 3 | Kentucky | Democratic-Republican | 1757–1840 |
| Alva B. Adams | 1923–1924 1933–1941 | 3 | Colorado | Democratic | 1875–1941 |
| Brock Adams | 1987–1993 | 3 | Washington | Democratic | 1927–2004 |
| John Quincy Adams | 1803–1808 | 1 | Massachusetts | Federalist | 1767–1848 |
| Robert H. Adams | 1830 | 2 | Mississippi | Democratic | 1792–1830 |
| Stephen Adams | 1852–1857 | 1 | Mississippi | Democratic | 1807–1857 |
| George Aiken | 1941–1975 | 3 | Vermont | Republican | 1892–1984 |
| Daniel Akaka | 1990–2013 | 1 | Hawaii | Democratic | 1924–2018 |
| James L. Alcorn | 1871–1877 | 2 | Mississippi | Republican | 1816–1894 |
| Nelson W. Aldrich | 1881–1911 | 1 | Rhode Island | Republican | 1841–1915 |
| Lamar Alexander | 2003–2021 | 2 | Tennessee | Republican | 1940–present |
| Russell A. Alger | 1902–1907 | 2 | Michigan | Republican | 1836–1907 |
| Wayne Allard | 1997–2009 | 2 | Colorado | Republican | 1943–present |
| J. Frank Allee | 1903–1907 | 2 | Delaware | Republican | 1857–1938 |
| George Allen | 2001–2007 | 1 | Virginia | Republican | 1952–present |
| Henry Justin Allen | 1929–1930 | 2 | Kansas | Republican | 1868–1950 |
| James Allen | 1969–1978 | 3 | Alabama | Democratic | 1912–1978 |
| John B. Allen | 1889–1893 1893 | 1 | Washington | Republican | 1845–1903 |
| Maryon Pittman Allen | 1978 | 3 | Alabama | Democratic | 1925–2018 |
| Philip Allen | 1853–1859 | 2 | Rhode Island | Democratic | 1785–1865 |
| William Allen | 1837–1849 | 3 | Ohio | Democratic | 1803–1879 |
| William V. Allen | 1893–1899 1899–1901 | 1 | Nebraska | Populist | 1847–1924 |
| William B. Allison | 1873–1908 | 3 | Iowa | Republican | 1829–1908 |
| Gordon Allott | 1955–1973 | 2 | Colorado | Republican | 1907–1989 |
| Adelbert Ames | 1870–1874 | 1 | Mississippi | Republican | 1835–1933 |
| Alexander O. Anderson | 1840–1841 | 2 | Tennessee | Democratic | 1794–1869 |
| Clinton Anderson | 1949–1973 | 2 | New Mexico | Democratic | 1895–1975 |
| Joseph Anderson | 1797–1815 | 1, 2 | Tennessee | Democratic-Republican | 1757–1837 |
| Wendell R. Anderson | 1976–1978 | 2 | Minnesota | Democratic | 1933–2016 |
| Charles O. Andrews | 1936–1946 | 1 | Florida | Democratic | 1877–1946 |
| Mark Andrews | 1981–1987 | 3 | North Dakota | Republican | 1926–2020 |
| Levi Ankeny | 1903–1909 | 3 | Washington | Republican | 1844–1921 |
| Henry B. Anthony | 1859–1884 | 2 | Rhode Island | Republican | 1815–1884 |
| William S. Archer | 1841–1847 | 2 | Virginia | Whig | 1789–1855 |
| David H. Armstrong | 1877–1879 | 3 | Missouri | Democratic | 1812–1893 |
| John Armstrong Jr. | 1800–1802 1803–1804 | 1, 3 | New York | Democratic-Republican | 1758–1843 |
| William L. Armstrong | 1979–1991 | 2 | Colorado | Republican | 1937–2016 |
| Samuel G. Arnold | 1862–1863 | 1 | Rhode Island | Republican | 1821–1880 |
| John Ashcroft | 1995–2001 | 1 | Missouri | Republican | 1942–present |
| Chester Ashley | 1844–1848 | 2 | Arkansas | Democratic | 1790–1848 |
| Eli P. Ashmun | 1816–1818 | 1 | Massachusetts | Federalist | 1770–1819 |
| Henry F. Ashurst | 1912–1941 | 1 | Arizona | Democratic | 1874–1962 |
| David Rice Atchison | 1843–1855 | 3 | Missouri | Democratic | 1807–1886 |
| Charles G. Atherton | 1843–1849 1853 | 2, 3 | New Hampshire | Democratic | 1804–1853 |
| Warren Austin | 1931–1946 | 1 | Vermont | Republican | 1877–1962 |
| Kelly Ayotte | 2011–2017 | 3 | New Hampshire | Republican | 1968–present |
| Nathan L. Bachman | 1933–1937 | 2 | Tennessee | Democratic | 1878–1937 |
| Augustus Octavius Bacon | 1895–1914 | 2 | Georgia | Democratic | 1839–1914 |
| George Edmund Badger | 1846–1855 | 1 | North Carolina | Whig | 1795–1866 |
| Arthur P. Bagby | 1841–1848 | 1 | Alabama | Democratic | 1794–1858 |
| James E. Bailey | 1877–1881 | 3 | Tennessee | Democratic | 1822–1885 |
| Joseph Weldon Bailey | 1901–1913 | 2 | Texas | Democratic | 1862–1929 |
| Josiah Bailey | 1931–1946 | 2 | North Carolina | Democratic | 1873–1946 |
| Theodorus Bailey | 1803–1804 | 1 | New York | Democratic-Republican | 1758–1828 |
| David Baird Jr. | 1929–1930 | 2 | New Jersey | Republican | 1881–1955 |
| David Baird Sr. | 1918–1919 | 2 | New Jersey | Republican | 1839–1927 |
| David J. Baker | 1830 | 2 | Illinois | Democratic | 1792–1869 |
| Edward Dickinson Baker | 1860–1861 | 2 | Oregon | Republican | 1811–1861 |
| Howard Baker | 1967–1985 | 2 | Tennessee | Republican | 1925–2014 |
| Lucien Baker | 1895–1901 | 2 | Kansas | Republican | 1846–1907 |
| Abraham Baldwin | 1799–1807 | 2 | Georgia | Democratic-Republican | 1754–1807 |
| Henry P. Baldwin | 1879–1881 | 1 | Michigan | Republican | 1814–1892 |
| Raymond E. Baldwin | 1946–1949 | 1 | Connecticut | Republican | 1893–1986 |
| Roger Sherman Baldwin | 1847–1851 | 1 | Connecticut | Whig | 1793–1863 |
| Joseph H. Ball | 1940–1942 1943–1949 | 2 | Minnesota | Republican | 1905–1993 |
| L. Heisler Ball | 1903–1905 1919–1925 | 1, 2 | Delaware | Republican | 1861–1932 |
| John H. Bankhead | 1907–1920 | 2 | Alabama | Democratic | 1842–1920 |
| John H. Bankhead II | 1931–1946 | 2 | Alabama | Democratic | 1872–1946 |
| James Barbour | 1815–1825 | 1 | Virginia | Democratic-Republican | 1775–1842 |
| John S. Barbour Jr. | 1889–1892 | 2 | Virginia | Democratic | 1820–1892 |
| William Warren Barbour | 1931–1937 1938–1943 | 1, 2 | New Jersey | Republican | 1888–1943 |
| Thomas R. Bard | 1900–1905 | 1 | California | Republican | 1841–1915 |
| Alben W. Barkley | 1927–1949 1955–1956 | 3 2 | Kentucky | Democratic | 1877–1956 |
| Dean Barkley | 2002–2003 | 2 | Minnesota | Independence | 1950–present |
| Isaac D. Barnard | 1827–1831 | 1 | Pennsylvania | Democratic | 1791–1834 |
| William Henry Barnum | 1876–1879 | 3 | Connecticut | Democratic | 1818–1889 |
| Robert Woodward Barnwell | 1850 | 2 | South Carolina | Democratic | 1801–1882 |
| Frank A. Barrett | 1953–1959 | 1 | Wyoming | Republican | 1892–1962 |
| Alexander Barrow | 1841–1846 | 2 | Louisiana | Whig | 1801–1846 |
| Middleton P. Barrow | 1882–1883 | 2 | Georgia | Democratic | 1839–1903 |
| Alexander G. Barry | 1938–1939 | 3 | Oregon | Republican | 1892–1952 |
| William T. Barry | 1814–1816 | 2 | Kentucky | Democratic-Republican | 1784–1835 |
| Bob Bartlett | 1959–1968 | 2 | Alaska | Democratic | 1904–1968 |
| Dewey F. Bartlett | 1973–1979 | 2 | Oklahoma | Republican | 1919–1979 |
| David Barton | 1821–1824 1824–1831 | 3 | Missouri | Democratic-Republican National Republican | 1783–1837 |
| Ross Bass | 1964–1967 | 2 | Tennessee | Democratic | 1918–1993 |
| Richard Bassett | 1789–1793 | 2 | Delaware | Federalist | 1745–1815 |
| William B. Bate | 1887–1905 | 1 | Tennessee | Democratic | 1826–1905 |
| Ephraim Bateman | 1826–1829 | 1 | New Jersey | National Republican | 1780–1829 |
| Isaac C. Bates | 1841–1845 | 2 | Massachusetts | Whig | 1779–1845 |
| Martin W. Bates | 1857–1859 | 2 | Delaware | Democratic | 1786–1869 |
| Max Baucus | 1978–2014 | 2 | Montana | Democratic | 1941–present |
| James A. Bayard | 1804–1813 | 2 | Delaware | Federalist | 1767–1815 |
| James A. Bayard Jr. | 1851–1864 1867–1869 | 1 | Delaware | Democratic | 1799–1880 |
| Richard H. Bayard | 1836–1839 1841–1845 | 1 | Delaware | Whig | 1796–1868 |
| Thomas F. Bayard | 1869–1885 | 1 | Delaware | Democratic | 1828–1898 |
| Thomas F. Bayard Jr. | 1922–1929 | 1 | Delaware | Democratic | 1868–1942 |
| Birch Bayh | 1963–1981 | 3 | Indiana | Democratic | 1928–2019 |
| Evan Bayh | 1999–2011 | 3 | Indiana | Democratic | 1955–present |
| J. Glenn Beall | 1953–1965 | 1 | Maryland | Republican | 1894–1971 |
| J. Glenn Beall Jr. | 1971–1977 | 1 | Maryland | Republican | 1927–2006 |
| James B. Beck | 1877–1890 | 2 | Kentucky | Democratic | 1822–1890 |
| J. C. W. Beckham | 1915–1921 | 3 | Kentucky | Democratic | 1869–1940 |
| Mark Begich | 2009–2015 | 2 | Alaska | Democratic | 1962–present |
| Charles H. Bell | 1879 | 3 | New Hampshire | Republican | 1823–1893 |
| James Bell | 1855–1856 1856–1857 | 3 | New Hampshire | Whig Republican | 1804–1857 |
| John Bell | 1847–1853 1853–1856 1856–1859 | 2 | Tennessee | Whig Whig American | 1796–1869 |
| Samuel Bell | 1823–1824 1824–1835 | 2 | New Hampshire | Democratic-Republican National Republican | 1770–1850 |
| Henry Bellmon | 1969–1981 | 3 | Oklahoma | Republican | 1921–2009 |
| George H. Bender | 1954–1957 | 3 | Ohio | Republican | 1896–1961 |
| Christie Benet | 1918 | 2 | South Carolina | Democratic | 1879–1951 |
| Judah P. Benjamin | 1853–1856 1856–1861 | 2 | Louisiana | Whig Democratic | 1811–1884 |
| Bob Bennett | 1993–2011 | 3 | Utah | Republican | 1933–2016 |
| Wallace F. Bennett | 1951–1974 | 3 | Utah | Republican | 1898–1993 |
| Alfred W. Benson | 1906–1907 | 2 | Kansas | Republican | 1843–1916 |
| Elmer Austin Benson | 1935–1936 | 2 | Minnesota | Farmer–Labor | 1895–1985 |
| Thomas Hart Benton | 1821–1824 1824–1851 | 1 | Missouri | Democratic-Republican Democratic | 1782–1858 |
| William Benton | 1949–1953 | 1 | Connecticut | Democratic | 1900–1973 |
| Lloyd Bentsen | 1971–1993 | 1 | Texas | Democratic | 1921–2006 |
| John M. Berrien | 1825–1829 1841–1845 1845–1847 1847–1852 | 2, 3 | Georgia | Democratic Whig Whig Whig | 1781–1856 |
| George L. Berry | 1937–1938 | 2 | Tennessee | Democratic | 1882–1948 |
| James Henderson Berry | 1885–1907 | 2 | Arkansas | Democratic | 1841–1913 |
| Thaddeus Betts | 1839–1840 | 1 | Connecticut | Whig | 1789–1840 |
| Albert J. Beveridge | 1899–1911 | 1 | Indiana | Republican | 1862–1927 |
| George M. Bibb | 1811–1814 1829–1835 | 2 | Kentucky | Democratic-Republican Democratic | 1776–1859 |
| William Wyatt Bibb | 1813–1816 | 2 | Georgia | Democratic-Republican | 1781–1820 |
| Alan Bible | 1954–1974 | 3 | Nevada | Democratic | 1909–1988 |
| Joe Biden | 1973–2009 | 2 | Delaware | Democratic | 1942–present |
| Asa Biggs | 1855–1858 | 3 | North Carolina | Democratic | 1811–1878 |
| William Bigler | 1856–1861 | 3 | Pennsylvania | Democratic | 1814–1880 |
| Theodore G. Bilbo | 1935–1947 | 1 | Mississippi | Democratic | 1877–1947 |
| Jeff Bingaman | 1983–2013 | 1 | New Mexico | Democratic | 1943–present |
| Hiram Bingham III | 1924–1933 | 3 | Connecticut | Republican | 1875–1956 |
| Kinsley S. Bingham | 1859–1861 | 2 | Michigan | Republican | 1808–1861 |
| William Bingham | 1795–1801 | 3 | Pennsylvania | Federalist | 1752–1804 |
| Hugo Black | 1927–1937 | 3 | Alabama | Democratic | 1886–1971 |
| John Black | 1832–1833 1833–1836 1836–1838 | 1 | Mississippi | Democratic National Republican Whig | 1800–1854 |
| J. C. S. Blackburn | 1885–1897 1901–1907 | 3 2 | Kentucky | Democratic | 1838–1918 |
| James G. Blaine | 1876–1881 | 2 | Maine | Republican | 1830–1893 |
| John J. Blaine | 1927–1933 | 3 | Wisconsin | Republican | 1875–1934 |
| Francis Preston Blair Jr. | 1871–1873 | 3 | Missouri | Democratic | 1821–1875 |
| Henry W. Blair | 1879–1885 1885–1891 | 3 | New Hampshire | Republican | 1834–1920 |
| William A. Blakley | 1957 1961 | 1, 2 | Texas | Democratic | 1898–1976 |
| Newton C. Blanchard | 1894–1897 | 3 | Louisiana | Democratic | 1849–1922 |
| Coleman Livingston Blease | 1925–1931 | 2 | South Carolina | Democratic | 1868–1942 |
| Jesse Bledsoe | 1813–1814 | 3 | Kentucky | Democratic-Republican | 1776–1836 |
| Rufus Blodgett | 1887–1893 | 1 | New Jersey | Democratic | 1834–1910 |
| Timothy Bloodworth | 1795–1801 | 3 | North Carolina | Democratic-Republican | 1736–1814 |
| William Blount | 1796–1797 | 2 | Tennessee | Democratic-Republican | 1749–1800 |
| Roy Blunt | 2011–2023 | 3 | Missouri | Republican | 1950–present |
| Elijah Boardman | 1821–1823 | 1 | Connecticut | Democratic-Republican | 1760–1823 |
| J. Caleb Boggs | 1961–1973 | 2 | Delaware | Republican | 1909–1993 |
| Lewis V. Bogy | 1873–1877 | 3 | Missouri | Democratic | 1813–1877 |
| Kit Bond | 1987–2011 | 3 | Missouri | Republican | 1939–present |
| Homer Bone | 1933–1944 | 3 | Washington | Democratic | 1883–1970 |
| Newton Booth | 1875–1881 | 1 | California | Anti-Monopolist | 1825–1892 |
| William Borah | 1907–1940 | 2 | Idaho | Republican | 1865–1940 |
| Arthur I. Boreman | 1869–1875 | 1 | West Virginia | Republican | 1823–1896 |
| David Boren | 1979–1994 | 2 | Oklahoma | Democratic | 1941–2025 |
| Solon Borland | 1848–1853 | 3 | Arkansas | Democratic | 1808–1864 |
| Rudy Boschwitz | 1978–1991 | 2 | Minnesota | Republican | 1930–present |
| Joseph H. Bottum | 1962–1963 | 3 | South Dakota | Republican | 1903–1984 |
| Charles Dominique Joseph Bouligny | 1824–1829 | 2 | Louisiana | National Republican | 1773–1833 |
| Jonathan Bourne Jr. | 1907–1913 | 2 | Oregon | Republican | 1855–1940 |
| George S. Boutwell | 1873–1877 | 2 | Massachusetts | Republican | 1818–1905 |
| Lemuel J. Bowden | 1863–1864 | 1 | Virginia | Union | 1815–1864 |
| Thomas M. Bowen | 1883–1889 | 2 | Colorado | Republican | 1835–1906 |
| Eva Bowring | 1954 | 2 | Nebraska | Republican | 1892–1985 |
| Barbara Boxer | 1993–2017 | 3 | California | Democratic | 1940–present |
| James W. Bradbury | 1847–1853 | 2 | Maine | Democratic | 1802–1901 |
| William Bradford | 1793–1797 | 2 | Rhode Island | Federalist | 1729–1808 |
| Bill Bradley | 1979–1997 | 2 | New Jersey | Democratic | 1943–present |
| Stephen R. Bradley | 1791–1795 1801–1813 | 3 | Vermont | Democratic-Republican | 1754–1830 |
| William O'Connell Bradley | 1909–1914 | 3 | Kentucky | Republican | 1847–1914 |
| James H. Brady | 1913–1918 | 1 | Idaho | Republican | 1862–1918 |
| Nicholas F. Brady | 1982 | 1 | New Jersey | Republican | 1930–present |
| Thomas Bragg | 1859–1861 | 2 | North Carolina | Democratic | 1810–1872 |
| Lawrence Brainerd | 1854–1855 | 3 | Vermont | Free Soil | 1794–1870 |
| John Branch | 1823–1829 | 2 | North Carolina | Democratic | 1782–1863 |
| Frank B. Brandegee | 1905–1924 | 3 | Connecticut | Republican | 1864–1924 |
| Sam G. Bratton | 1925–1933 | 2 | New Mexico | Democratic | 1888–1963 |
| John Breaux | 1987–2005 | 3 | Louisiana | Democratic | 1944–present |
| John Breckinridge | 1801–1805 | 3 | Kentucky | Democratic-Republican | 1760–1806 |
| John C. Breckinridge | 1861 | 3 | Kentucky | Democratic | 1821–1875 |
| Sidney Breese | 1843–1849 | 3 | Illinois | Democratic | 1800–1878 |
| Richard Brent | 1809–1814 | 1 | Virginia | Democratic-Republican | 1757–1814 |
| Daniel Brewster | 1963–1969 | 3 | Maryland | Democratic | 1923–2007 |
| Ralph Owen Brewster | 1941–1952 | 1 | Maine | Republican | 1888–1961 |
| Calvin S. Brice | 1891–1897 | 3 | Ohio | Democratic | 1845–1898 |
| John W. Bricker | 1947–1959 | 1 | Ohio | Republican | 1893–1986 |
| Styles Bridges | 1937–1961 | 2 | New Hampshire | Republican | 1898–1961 |
| Frank O. Briggs | 1907–1913 | 2 | New Jersey | Republican | 1851–1913 |
| Frank P. Briggs | 1945–1947 | 1 | Missouri | Democratic | 1894–1992 |
| Jesse D. Bright | 1845–1862 | 1 | Indiana | Democratic | 1812–1875 |
| Joseph L. Bristow | 1909–1915 | 3 | Kansas | Republican | 1861–1944 |
| Bill Brock | 1971–1977 | 1 | Tennessee | Republican | 1930–2021 |
| William E. Brock | 1929–1931 | 2 | Tennessee | Democratic | 1872–1950 |
| David C. Broderick | 1857–1859 | 1 | California | Democratic | 1820–1859 |
| Richard Brodhead | 1851–1857 | 1 | Pennsylvania | Democratic | 1811–1863 |
| Edward Brooke | 1967–1979 | 2 | Massachusetts | Republican | 1919–2015 |
| Walker Brooke | 1852–1853 | 2 | Mississippi | Whig | 1813–1869 |
| Smith W. Brookhart | 1922–1926 1927–1933 | 2, 3 | Iowa | Republican | 1869–1944 |
| Charles W. Brooks | 1940–1949 | 2 | Illinois | Republican | 1897–1957 |
| J. Melville Broughton | 1948–1949 | 2 | North Carolina | Democratic | 1888–1949 |
| Edwin S. Broussard | 1921–1933 | 3 | Louisiana | Democratic | 1874–1934 |
| Robert F. Broussard | 1915–1918 | 3 | Louisiana | Democratic | 1864–1918 |
| Albert G. Brown | 1854–1861 | 2 | Mississippi | Democratic | 1813–1880 |
| Arthur Brown | 1896–1897 | 3 | Utah | Republican | 1843–1906 |
| Bedford Brown | 1829–1840 | 2 | North Carolina | Democratic | 1795–1870 |
| Benjamin Gratz Brown | 1863–1867 | 3 | Missouri | Republican | 1826–1885 |
| Ernest S. Brown | 1954 | 3 | Nevada | Republican | 1903–1965 |
| Ethan Allen Brown | 1822–1824 1824–1825 | 3 | Ohio | Democratic-Republican National Republican | 1776–1852 |
| Fred H. Brown | 1933–1939 | 3 | New Hampshire | Democratic | 1879–1955 |
| Hank Brown | 1991–1997 | 2 | Colorado | Republican | 1940–present |
| James Brown | 1813–1817 1819–1823 | 2, 3 | Louisiana | Democratic-Republican | 1766–1835 |
| John Brown | 1792–1805 | 2 | Kentucky | Democratic-Republican | 1757–1837 |
| Joseph E. Brown | 1880–1891 | 3 | Georgia | Democratic | 1821–1894 |
| Norris Brown | 1907–1913 | 2 | Nebraska | Republican | 1863–1960 |
| Prentiss M. Brown | 1936–1943 | 2 | Michigan | Democratic | 1889–1973 |
| Scott Brown | 2010–2013 | 1 | Massachusetts | Republican | 1959–present |
| Sam Brownback | 1996–2011 | 3 | Kansas | Republican | 1956–present |
| Sherrod Brown | 2007–2025 | 1 | Ohio | Democratic | 1952–present |
| Orville Hickman Browning | 1861–1863 | 2 | Illinois | Republican | 1806–1881 |
| William G. Brownlow | 1869–1875 | 1 | Tennessee | Republican | 1805–1877 |
| Jim Broyhill | 1986 | 3 | North Carolina | Republican | 1927–2023 |
| Blanche Bruce | 1875–1881 | 1 | Mississippi | Republican | 1841–1898 |
| William Cabell Bruce | 1923–1929 | 1 | Maryland | Democratic | 1860–1946 |
| Norman Brunsdale | 1959–1960 | 1 | North Dakota | Republican | 1891–1978 |
| Nathan Philemon Bryan | 1911–1917 | 1 | Florida | Democratic | 1872–1935 |
| Richard Bryan | 1989–2001 | 1 | Nevada | Democratic | 1937–present |
| William James Bryan | 1907–1908 | 3 | Florida | Democratic | 1876–1908 |
| James Buchanan | 1834–1845 | 3 | Pennsylvania | Democratic | 1791–1868 |
| C. Douglass Buck | 1943–1949 | 2 | Delaware | Republican | 1890–1965 |
| Charles R. Buckalew | 1863–1869 | 1 | Pennsylvania | Democratic | 1821–1899 |
| William Alfred Buckingham | 1869–1875 | 1 | Connecticut | Republican | 1804–1875 |
| James L. Buckley | 1971–1976 1976–1977 | 1 | New York | Conservative Republican | 1923–2023 |
| Alexander Buckner | 1831–1833 | 3 | Missouri | Democratic | 1785–1833 |
| Morgan Bulkeley | 1905–1911 | 1 | Connecticut | Republican | 1837–1922 |
| Robert J. Bulkley | 1930–1939 | 3 | Ohio | Democratic | 1880–1965 |
| William Bellinger Bulloch | 1813 | 2 | Georgia | Democratic-Republican | 1777–1852 |
| William J. Bulow | 1931–1943 | 2 | South Dakota | Democratic | 1869–1960 |
| Dale Bumpers | 1975–1999 | 3 | Arkansas | Democratic | 1925–2016 |
| Berkeley L. Bunker | 1940–1942 | 1 | Nevada | Democratic | 1906–1999 |
| Jim Bunning | 1999–2011 | 3 | Kentucky | Republican | 1931–2017 |
| Thomas G. Burch | 1946 | 2 | Virginia | Democratic | 1869–1951 |
| Jocelyn Burdick | 1992 | 1 | North Dakota | Democratic | 1922–2019 |
| Quentin Burdick | 1961–1992 | 1 | North Dakota | Democratic | 1908–1992 |
| Edward R. Burke | 1935–1941 | 3 | Nebraska | Democratic | 1880–1968 |
| Thomas A. Burke | 1953–1954 | 3 | Ohio | Democratic | 1898–1971 |
| Elmer Burkett | 1905–1911 | 1 | Nebraska | Republican | 1867–1935 |
| Edwin C. Burleigh | 1913–1916 | 2 | Maine | Republican | 1843–1916 |
| Jacob Burnet | 1828–1831 | 3 | Ohio | National Republican | 1770–1853 |
| Henry E. Burnham | 1901–1913 | 2 | New Hampshire | Republican | 1844–1917 |
| Conrad Burns | 1989–2007 | 1 | Montana | Republican | 1935–2016 |
| Ambrose Burnside | 1875–1881 | 1 | Rhode Island | Republican | 1824–1881 |
| Aaron Burr | 1791–1797 | 1 | New York | Democratic-Republican | 1756–1836 |
| Richard Burr | 2005–2023 | 3 | North Carolina | Republican | 1955–present |
| James Burrill Jr. | 1817–1820 | 2 | Rhode Island | Federalist | 1772–1820 |
| Roland Burris | 2009–2010 | 3 | Illinois | Democratic | 1937–present |
| Julius C. Burrows | 1895–1911 | 1 | Michigan | Republican | 1837–1915 |
| Holm O. Bursum | 1921–1925 | 2 | New Mexico | Republican | 1867–1953 |
| Harold Hitz Burton | 1941–1945 | 1 | Ohio | Republican | 1888–1964 |
| Joseph R. Burton | 1901–1906 | 2 | Kansas | Republican | 1852–1923 |
| Theodore E. Burton | 1909–1915 1928–1929 | 3 | Ohio | Republican | 1851–1929 |
| Prescott Bush | 1953–1963 | 3 | Connecticut | Republican | 1895–1972 |
| Harlan J. Bushfield | 1943–1948 | 2 | South Dakota | Republican | 1882–1948 |
| Vera C. Bushfield | 1948 | 2 | South Dakota | Republican | 1889–1976 |
| Andrew Butler | 1846–1857 | 3 | South Carolina | Democratic | 1796–1857 |
| Hugh A. Butler | 1941–1954 | 1 | Nebraska | Republican | 1878–1954 |
| John Marshall Butler | 1951–1963 | 3 | Maryland | Republican | 1897–1978 |
| Laphonza Butler | 2023–2024 | 1 | California | Democratic | 1979–present |
| Marion Butler | 1895–1901 | 1 | North Carolina | Populist | 1863–1938 |
| Matthew Butler | 1877–1895 | 2 | South Carolina | Democratic | 1836–1909 |
| Pierce Butler | 1789–1795 1795–1796 1802–1804 | 2, 3 | South Carolina | Federalist Democratic-Republican Democratic-Republican | 1744–1822 |
| William M. Butler | 1924–1926 | 1 | Massachusetts | Republican | 1861–1937 |
| Harry F. Byrd | 1933–1965 | 1 | Virginia | Democratic | 1887–1966 |
| Harry F. Byrd Jr. | 1965–1970 1970–1983 | 1 | Virginia | Democratic Independent | 1914–2013 |
| Robert Byrd | 1959–2010 | 1 | West Virginia | Democratic | 1917–2010 |
| James F. Byrnes | 1931–1941 | 2 | South Carolina | Democratic | 1882–1972 |
| George Cabot | 1791–1796 | 1 | Massachusetts | Federalist | 1752–1823 |
| Donelson Caffery | 1892–1901 | 2 | Louisiana | Democratic | 1835–1906 |
| Harry P. Cain | 1946–1953 | 1 | Washington | Republican | 1906–1979 |
| William M. Calder | 1917–1923 | 1 | New York | Republican | 1869–1945 |
| Alexander Caldwell | 1871–1873 | 2 | Kansas | Republican | 1830–1917 |
| John C. Calhoun | 1832–1837 1837–1843 1845–1850 | 2 | South Carolina | Nullifier Democratic Democratic | 1782–1850 |
| Wilkinson Call | 1879–1897 | 3 | Florida | Democratic | 1834–1910 |
| Johnson N. Camden | 1881–1887 1893–1895 | 1, 2 | West Virginia | Democratic | 1828–1908 |
| Johnson N. Camden Jr. | 1914–1915 | 3 | Kentucky | Democratic | 1865–1942 |
| Angus Cameron | 1875–1881 1881–1885 | 1, 3 | Wisconsin | Republican | 1826–1897 |
| J. Donald Cameron | 1877–1897 | 3 | Pennsylvania | Republican | 1833–1918 |
| Ralph H. Cameron | 1921–1927 | 3 | Arizona | Republican | 1863–1953 |
| Simon Cameron | 1845–1849 1857–1861 1867–1877 | 1, 3 | Pennsylvania | Democratic Republican Republican | 1799–1889 |
| Alexander Campbell | 1809–1813 | 3 | Ohio | Democratic-Republican | 1779–1857 |
| Ben Nighthorse Campbell | 1993–1995 1995–2005 | 3 | Colorado | Democratic Republican | 1933–present |
| George W. Campbell | 1811–1814 1815–1818 | 1, 2 | Tennessee | Democratic-Republican | 1769–1848 |
| Frank J. Cannon | 1896 1896–1899 | 1 | Utah | Republican Silver Republican | 1859–1933 |
| Howard Cannon | 1959–1983 | 1 | Nevada | Democratic | 1912–2002 |
| Homer E. Capehart | 1945–1963 | 3 | Indiana | Republican | 1897–1979 |
| Allen T. Caperton | 1875–1876 | 1 | West Virginia | Democratic | 1810–1876 |
| Arthur Capper | 1919–1949 | 2 | Kansas | Republican | 1865–1951 |
| Hattie Wyatt Caraway | 1931–1945 | 3 | Arkansas | Democratic | 1878–1950 |
| Thaddeus H. Caraway | 1921–1931 | 3 | Arkansas | Democratic | 1871–1931 |
| Ben Cardin | 2007–2025 | 1 | Maryland | Democratic | 1943–present |
| Joseph M. Carey | 1890–1895 | 2 | Wyoming | Republican | 1845–1924 |
| Robert D. Carey | 1930–1937 | 2 | Wyoming | Republican | 1878–1937 |
| John S. Carlile | 1861–1865 | 2 | Virginia | Union | 1817–1878 |
| John G. Carlisle | 1890–1893 | 2 | Kentucky | Democratic | 1834–1910 |
| Frank Carlson | 1950–1969 | 3 | Kansas | Republican | 1893–1987 |
| Edward W. Carmack | 1901–1907 | 2 | Tennessee | Democratic | 1858–1908 |
| Jean Carnahan | 2001–2002 | 1 | Missouri | Democratic | 1933–2024 |
| Matthew H. Carpenter | 1869–1875 1879–1881 | 1, 3 | Wisconsin | Republican | 1824–1881 |
| Tom Carper | 2001–2025 | 1 | Delaware | Democratic | 1947–present |
| Charles Carroll of Carrollton | 1789–1792 | 1 | Maryland | Federalist | 1737–1832 |
| John A. Carroll | 1957–1963 | 3 | Colorado | Democratic | 1901–1983 |
| Thomas H. Carter | 1895–1901 1905–1911 | 1, 2 | Montana | Republican | 1854–1911 |
| Edward P. Carville | 1945–1947 | 1 | Nevada | Democratic | 1885–1956 |
| Clifford P. Case | 1955–1979 | 2 | New Jersey | Republican | 1904–1982 |
| Francis H. Case | 1951–1962 | 3 | South Dakota | Republican | 1896–1962 |
| Bob Casey Jr. | 2007–2025 | 1 | Pennsylvania | Democratic | 1960–present |
| Lyman R. Casey | 1889–1893 | 1 | North Dakota | Republican | 1837–1914 |
| Lewis Cass | 1845–1848 1849–1857 | 1 | Michigan | Democratic | 1782–1866 |
| Eugene Casserly | 1869–1873 | 1 | California | Democratic | 1820–1883 |
| Charles W. Cathcart | 1852–1853 | 3 | Indiana | Democratic | 1809–1888 |
| Thomas B. Catron | 1912–1917 | 1 | New Mexico | Republican | 1840–1921 |
| Alexander G. Cattell | 1866–1871 | 2 | New Jersey | Republican | 1816–1894 |
| Jonathan Chace | 1885–1889 | 2 | Rhode Island | Republican | 1829–1917 |
| John Chafee | 1976–1999 | 1 | Rhode Island | Republican | 1922–1999 |
| Lincoln Chafee | 1999–2007 | 1 | Rhode Island | Republican | 1953–present |
| Jerome B. Chaffee | 1876–1879 | 3 | Colorado | Republican | 1825–1886 |
| Joseph W. Chalmers | 1845–1847 | 2 | Mississippi | Democratic | 1806–1853 |
| George Earle Chamberlain | 1909–1921 | 3 | Oregon | Democratic | 1854–1928 |
| Ezekiel F. Chambers | 1826–1834 | 3 | Maryland | National Republican | 1788–1867 |
| Henry H. Chambers | 1825–1826 | 3 | Alabama | Democratic | 1790–1867 |
| Saxby Chambliss | 2003–2015 | 1 | Georgia | Republican | 1943–present |
| Christopher G. Champlin | 1809–1811 | 1 | Rhode Island | Federalist | 1768–1840 |
| Happy Chandler | 1939–1945 | 2 | Kentucky | Democratic | 1898–1991 |
| John Chandler | 1820–1824 1824–1829 | 2 | Maine | Democratic-Republican Democratic | 1762–1841 |
| William E. Chandler | 1887–1889 1889–1901 | 2 | New Hampshire | Republican | 1835–1917 |
| Zachariah Chandler | 1857–1875 1879 | 1 | Michigan | Republican | 1813–1879 |
| Virgil Chapman | 1949–1951 | 2 | Kentucky | Democratic | 1895–1951 |
| Robert M. Charlton | 1852–1853 | 2 | Georgia | Democratic | 1807–1854 |
| Dudley Chase | 1813–1817 1825–1831 | 3 | Vermont | Democratic-Republican National Republican | 1771–1846 |
| Salmon P. Chase | 1849–1855 1861 | 3 | Ohio | Free Soil Republican | 1808–1873 |
| Dennis Chávez | 1935–1962 | 1 | New Mexico | Democratic | 1888–1962 |
| Person Colby Cheney | 1886–1887 | 2 | New Hampshire | Republican | 1828–1901 |
| James Chesnut Jr. | 1858–1860 | 3 | South Carolina | Democratic | 1815–1885 |
| Jeffrey Chiesa | 2013 | 2 | New Jersey | Republican | 1965–present |
| George M. Chilcott | 1882–1883 | 2 | Colorado | Republican | 1828–1891 |
| Lawton Chiles | 1971–1989 | 1 | Florida | Democratic | 1930–1998 |
| Horace Chilton | 1891–1892 1895–1901 | 1, 2 | Texas | Democratic | 1853–1932 |
| William E. Chilton | 1911–1917 | 1 | West Virginia | Democratic | 1858–1939 |
| Nathaniel Chipman | 1797–1803 | 1 | Vermont | Federalist | 1752–1843 |
| Rufus Choate | 1841–1845 | 1 | Massachusetts | Whig | 1799–1859 |
| Isaac P. Christiancy | 1875–1879 | 1 | Michigan | Republican | 1812–1890 |
| Frank Church | 1957–1981 | 3 | Idaho | Democratic | 1924–1984 |
| Joseph Cilley | 1846–1847 | 2 | New Hampshire | Liberty | 1791–1887 |
| William C. C. Claiborne | 1817 | 2 | Louisiana | Democratic-Republican | 1772–1817 |
| Moses E. Clapp | 1901–1917 | 1 | Minnesota | Republican | 1851–1929 |
| Bennett Champ Clark | 1933–1945 | 3 | Missouri | Democratic | 1890–1954 |
| Clarence D. Clark | 1895–1917 | 1 | Wyoming | Republican | 1851–1930 |
| Daniel Clark | 1857–1866 | 3 | New Hampshire | Republican | 1809–1891 |
| David Worth Clark | 1939–1945 | 3 | Idaho | Democratic | 1902–1955 |
| Dick Clark | 1973–1979 | 2 | Iowa | Democratic | 1928–2023 |
| Joseph S. Clark Jr. | 1957–1969 | 3 | Pennsylvania | Democratic | 1901–1990 |
| William A. Clark | 1899–1900 1901–1907 | 1, 2 | Montana | Democratic | 1839–1925 |
| James P. Clarke | 1903–1916 | 3 | Arkansas | Democratic | 1854–1916 |
| John Hopkins Clarke | 1847–1853 | 2 | Rhode Island | Whig | 1789–1870 |
| Alexander S. Clay | 1897–1910 | 3 | Georgia | Democratic | 1853–1910 |
| Clement Claiborne Clay | 1853–1861 | 1 | Alabama | Democratic | 1816–1882 |
| Clement Comer Clay | 1837–1841 | 3 | Alabama | Democratic | 1789–1866 |
| Henry Clay | 1806–1807 1810–1811 1831–1832 1832–1842 1849–1852 | 2, 3 | Kentucky | Democratic-Republican Democratic-Republican National Republican Whig Whig | 1777–1852 |
| John M. Clayton | 1829–1836 1845–1849 1853–1855 1855–1856 | 1, 2 | Delaware | National Republican Whig Whig Opposition | 1796–1856 |
| Joshua Clayton | 1798 | 2 | Delaware | Federalist | 1744–1798 |
| Powell Clayton | 1871–1877 | 2 | Arkansas | Republican | 1833–1914 |
| Thomas Clayton | 1824–1825 1825–1827 1837–1847 | 1, 2 | Delaware | Federalist National Republican Whig | 1777–1854 |
| Max Cleland | 1997–2003 | 2 | Georgia | Democratic | 1942–2021 |
| Jeremiah Clemens | 1849–1853 | 2 | Alabama | Democratic | 1814–1865 |
| Earle Clements | 1950–1957 | 3 | Kentucky | Democratic | 1896–1985 |
| Thomas Lanier Clingman | 1858–1861 | 3 | North Carolina | Democratic | 1812–1897 |
| DeWitt Clinton | 1802–1803 | 3 | New York | Democratic-Republican | 1769–1828 |
| Hillary Clinton | 2001–2009 | 1 | New York | Democratic | 1947–present |
| Dan Coats | 1989–1999 2011–2017 | 3 | Indiana | Republican | 1943–present |
| Thomas W. Cobb | 1824–1828 | 2 | Georgia | Democratic | 1784–1830 |
| Tom Coburn | 2005–2015 | 3 | Oklahoma | Republican | 1948–2020 |
| Thad Cochran | 1978–2018 | 2 | Mississippi | Republican | 1937–2019 |
| William Cocke | 1796–1797 1797 1799–1805 | 1, 2 | Tennessee | Democratic-Republican | 1748–1828 |
| Francis Cockrell | 1875–1905 | 1 | Missouri | Democratic | 1834–1915 |
| John S. Cohen | 1932–1933 | 2 | Georgia | Democratic | 1870–1935 |
| William Cohen | 1979–1997 | 2 | Maine | Republican | 1940–present |
| Richard Coke | 1877–1895 | 2 | Texas | Democratic | 1829–1897 |
| Cornelius Cole | 1867–1873 | 3 | California | Republican | 1822–1924 |
| Norm Coleman | 2003–2009 | 2 | Minnesota | Republican | 1949–present |
| John E. Colhoun | 1801–1802 | 3 | South Carolina | Democratic-Republican | 1749–1802 |
| Jacob Collamer | 1855–1857 1857–1865 | 3 | Vermont | Opposition Republican | 1791–1865 |
| Alfred H. Colquitt | 1883–1894 | 2 | Georgia | Democratic | 1824–1894 |
| Walter T. Colquitt | 1843–1848 | 3 | Georgia | Democratic | 1799–1855 |
| LeBaron Bradford Colt | 1913–1924 | 2 | Rhode Island | Republican | 1846–1924 |
| Joseph P. Comegys | 1856–1857 | 2 | Delaware | Opposition | 1813–1893 |
| B. B. Comer | 1920 | 2 | Alabama | Democratic | 1848–1927 |
| John Condit | 1803–1809 1809–1817 | 1, 2 | New Jersey | Democratic-Republican | 1755–1834 |
| Omar D. Conger | 1881–1887 | 1 | Michigan | Republican | 1818–1898 |
| Roscoe Conkling | 1867–1881 | 3 | New York | Republican | 1829–1888 |
| Tom Connally | 1929–1953 | 1 | Texas | Democratic | 1877–1963 |
| John Conness | 1863–1869 | 1 | California | Republican | 1821–1909 |
| Simon B. Conover | 1873–1879 | 3 | Florida | Republican | 1840–1908 |
| Charles Magill Conrad | 1842–1843 | 3 | Louisiana | Whig | 1804–1878 |
| Kent Conrad | 1987–1992 1992–2013 | 1, 3 | North Dakota | Democratic | 1948–present |
| Marlow Cook | 1968–1974 | 3 | Kentucky | Republican | 1926–2016 |
| Marcus A. Coolidge | 1931–1937 | 2 | Massachusetts | Democratic | 1865–1947 |
| Henry Cooper | 1871–1877 | 2 | Tennessee | Democratic | 1827–1884 |
| James Cooper | 1849–1855 | 3 | Pennsylvania | Whig | 1810–1863 |
| John Sherman Cooper | 1946–1949 1952–1955 1956–1973 | 2 | Kentucky | Republican | 1901–1991 |
| Royal S. Copeland | 1923–1938 | 1 | New York | Democratic | 1868–1938 |
| Henry W. Corbett | 1867–1873 | 3 | Oregon | Republican | 1827–1903 |
| Guy Cordon | 1944–1955 | 2 | Oregon | Republican | 1890–1969 |
| Bob Corker | 2007–2019 | 1 | Tennessee | Republican | 1952–present |
| Thomas Corwin | 1845–1850 | 1 | Ohio | Whig | 1794–1865 |
| Jon Corzine | 2001–2006 | 1 | New Jersey | Democratic | 1947–present |
| Edward P. Costigan | 1931–1937 | 2 | Colorado | Democratic | 1874–1939 |
| Norris Cotton | 1954–1974 1975 | 3 | New Hampshire | Republican | 1900–1989 |
| James J. Couzens | 1922–1936 | 2 | Michigan | Republican | 1872–1936 |
| Paul Coverdell | 1993–2000 | 3 | Georgia | Republican | 1939–2000 |
| Edgar Cowan | 1861–1867 | 3 | Pennsylvania | Republican | 1815–1885 |
| Mo Cowan | 2013 | 2 | Massachusetts | Democratic | 1969–present |
| Samuel C. Crafts | 1842–1843 | 3 | Vermont | Whig | 1768–1853 |
| Aaron H. Cragin | 1865–1877 | 2 | New Hampshire | Republican | 1821–1898 |
| Larry Craig | 1991–2009 | 2 | Idaho | Republican | 1945–present |
| Winthrop M. Crane | 1904–1913 | 2 | Massachusetts | Republican | 1853–1920 |
| Alan Cranston | 1969–1993 | 3 | California | Democratic | 1914–2000 |
| Coe I. Crawford | 1909–1915 | 3 | South Dakota | Republican | 1858–1944 |
| William H. Crawford | 1807–1813 | 2 | Georgia | Democratic-Republican | 1772–1834 |
| John Creswell | 1865–1867 | 3 | Maryland | Republican | 1828–1891 |
| Edward D. Crippa | 1954 | 2 | Wyoming | Republican | 1899–1960 |
| John J. Crittenden | 1817–1819 1835–1841 1842–1848 1855–1861 | 2, 3 | Kentucky | Democratic-Republican Whig Whig American | 1787–1863 |
| William E. Crow | 1921–1922 | 1 | Pennsylvania | Republican | 1870–1922 |
| Robert Crozier | 1873–1874 | 2 | Kansas | Republican | 1827–1895 |
| Charles Allen Culberson | 1899–1923 | 1 | Texas | Democratic | 1855–1925 |
| Shelby Moore Cullom | 1883–1913 | 2 | Illinois | Republican | 1829–1914 |
| John Culver | 1975–1981 | 3 | Iowa | Democratic | 1932–2018 |
| Albert B. Cummins | 1908–1926 | 3 | Iowa | Republican | 1850–1926 |
| Carl Curtis | 1955–1979 | 2 | Nebraska | Republican | 1905–2000 |
| Charles Curtis | 1907–1913 1915–1929 | 2, 3 | Kansas | Republican | 1860–1936 |
| Alfred Cuthbert | 1835–1843 | 3 | Georgia | Democratic | 1785–1856 |
| Bronson M. Cutting | 1927–1928 1929–1935 | 1 | New Mexico | Republican | 1888–1935 |
| Charles Cutts | 1810–1813 | 3 | New Hampshire | Democratic-Republican | 1769–1846 |
| Al D'Amato | 1981–1999 | 3 | New York | Republican | 1937–present |
| David Daggett | 1813–1819 | 3 | Connecticut | Federalist | 1764–1851 |
| Porter H. Dale | 1923–1933 | 3 | Vermont | Republican | 1867–1933 |
| George M. Dallas | 1831–1833 | 1 | Pennsylvania | Democratic | 1792–1864 |
| Tristram Dalton | 1789–1791 | 1 | Massachusetts | Federalist | 1738–1817 |
| Judah Dana | 1836–1837 | 1 | Maine | Democratic | 1772–1845 |
| Samuel W. Dana | 1810–1821 | 1 | Connecticut | Federalist | 1760–1830 |
| John A. Danaher | 1939–1945 | 3 | Connecticut | Republican | 1899–1990 |
| John Danforth | 1977–1995 | 1 | Missouri | Republican | 1936–present |
| Charles E. Daniel | 1954 | 2 | South Carolina | Democratic | 1895–1964 |
| John W. Daniel | 1887–1910 | 1 | Virginia | Democratic | 1842–1910 |
| Price Daniel | 1953–1957 | 1 | Texas | Democratic | 1910–1988 |
| Harry Darby | 1949–1950 | 3 | Kansas | Republican | 1895–1987 |
| Tom Daschle | 1987–2005 | 3 | South Dakota | Democratic | 1947–present |
| Franklin Davenport | 1798–1799 | 1 | New Jersey | Federalist | 1755–1832 |
| Cushman Kellogg Davis | 1887–1900 | 1 | Minnesota | Republican | 1838–1900 |
| David Davis | 1877–1883 | 2 | Illinois | Independent | 1815–1886 |
| Garrett Davis | 1861–1872 | 3 | Kentucky | Democratic | 1801–1872 |
| Henry G. Davis | 1871–1883 | 2 | West Virginia | Democratic | 1823–1916 |
| James J. Davis | 1930–1945 | 3 | Pennsylvania | Republican | 1873–1947 |
| Jeff Davis | 1907–1913 | 2 | Arkansas | Democratic | 1862–1913 |
| Jefferson Davis | 1847–1851 1857–1861 | 1 | Mississippi | Democratic | 1807/1808–1889 |
| John Davis | 1835–1836 1836–1841 1845–1853 | 2 | Massachusetts | National Republican Whig Whig | 1787–1854 |
| Henry L. Dawes | 1875–1893 | 1 | Massachusetts | Republican | 1816–1903 |
| William Crosby Dawson | 1849–1855 | 3 | Georgia | Whig | 1798–1856 |
| Jonathan Dayton | 1799–1805 | 2 | New Jersey | Federalist | 1760–1824 |
| Mark Dayton | 2001–2007 | 1 | Minnesota | Democratic | 1947–present |
| William L. Dayton | 1842–1851 | 1 | New Jersey | Whig | 1807–1864 |
| William F. De Saussure | 1852–1853 | 2 | South Carolina | Democratic | 1792–1870 |
| William Joseph Deboe | 1897–1903 | 3 | Kentucky | Republican | 1849–1927 |
| Dennis DeConcini | 1977–1995 | 1 | Arizona | Democratic | 1937–present |
| Jim DeMint | 2005–2013 | 3 | South Carolina | Republican | 1951–present |
| Charles S. Deneen | 1925–1931 | 2 | Illinois | Republican | 1863–1940 |
| George R. Dennis | 1873–1879 | 3 | Maryland | Democratic | 1822–1882 |
| Jeremiah Denton | 1981–1987 | 3 | Alabama | Republican | 1924–2014 |
| Chauncey Depew | 1899–1911 | 1 | New York | Republican | 1834–1928 |
| Jean Noël Destréhan | 1812 | 2 | Louisiana | Democratic-Republican | 1754–1823 |
| Mike DeWine | 1995–2007 | 3 | Ohio | Republican | 1947–present |
| James DeWolf | 1821–1824 1824–1825 | 1 | Rhode Island | Democratic-Republican Democratic | 1764–1837 |
| Samuel Dexter | 1799–1800 | 2 | Massachusetts | Federalist | 1761–1816 |
| Nathaniel B. Dial | 1919–1925 | 2 | South Carolina | Democratic | 1862–1940 |
| Charles W. F. Dick | 1904–1911 | 1 | Ohio | Republican | 1858–1945 |
| Mahlon Dickerson | 1817–1824 1824–1833 | 1, 2 | New Jersey | Democratic-Republican Democratic | 1770–1853 |
| Daniel S. Dickinson | 1844–1851 | 2 | New York | Democratic | 1800–1866 |
| Lester J. Dickinson | 1931–1937 | 2 | Iowa | Republican | 1873–1968 |
| Philemon Dickinson | 1790–1793 | 2 | New Jersey | Federalist | 1739–1809 |
| William H. Dieterich | 1933–1939 | 3 | Illinois | Democratic | 1876–1940 |
| Charles Henry Dietrich | 1901–1905 | 1 | Nebraska | Republican | 1853–1924 |
| Clarence Dill | 1923–1935 | 1 | Washington | Democratic | 1884–1978 |
| William P. Dillingham | 1900–1923 | 3 | Vermont | Republican | 1843–1923 |
| Everett Dirksen | 1951–1969 | 3 | Illinois | Republican | 1896–1969 |
| John Adams Dix | 1845–1849 | 3 | New York | Democratic | 1798–1879 |
| Alan J. Dixon | 1981–1993 | 3 | Illinois | Democratic | 1927–2014 |
| Archibald Dixon | 1852–1855 | 3 | Kentucky | Whig | 1802–1876 |
| James Dixon | 1857–1869 | 1 | Connecticut | Republican | 1814–1873 |
| Joseph M. Dixon | 1907–1912 1912–1913 | 2 | Montana | Republican Progressive | 1867–1934 |
| Nathan F. Dixon I | 1839–1842 | 1 | Rhode Island | Whig | 1774–1842 |
| Nathan F. Dixon III | 1889–1895 | 2 | Rhode Island | Republican | 1847–1897 |
| Chris Dodd | 1981–2011 | 3 | Connecticut | Democratic | 1944–present |
| Thomas J. Dodd | 1959–1971 | 1 | Connecticut | Democratic | 1907–1971 |
| Augustus C. Dodge | 1846–1855 | 3 | Iowa | Democratic | 1812–1883 |
| Henry Dodge | 1848–1857 | 1 | Wisconsin | Democratic | 1782–1867 |
| Bob Dole | 1969–1996 | 3 | Kansas | Republican | 1923–2021 |
| Elizabeth Dole | 2003–2009 | 2 | North Carolina | Republican | 1936–present |
| Jonathan P. Dolliver | 1900–1910 | 2 | Iowa | Republican | 1858–1910 |
| Joseph N. Dolph | 1883–1895 | 2 | Oregon | Republican | 1835–1897 |
| Pete Domenici | 1973–2009 | 2 | New Mexico | Republican | 1932–2017 |
| Peter H. Dominick | 1963–1975 | 3 | Colorado | Republican | 1915–1981 |
| A. Victor Donahey | 1935–1941 | 1 | Ohio | Democratic | 1873–1946 |
| Forrest C. Donnell | 1945–1951 | 3 | Missouri | Republican | 1884–1980 |
| Joe Donnelly | 2013–2019 | 1 | Indiana | Democratic | 1955–present |
| James Rood Doolittle | 1857–1869 | 1 | Wisconsin | Republican | 1815–1897 |
| Byron Dorgan | 1992–2011 | 3 | North Dakota | Democratic | 1942–present |
| Stephen Wallace Dorsey | 1873–1879 | 3 | Arkansas | Republican | 1842–1916 |
| Paul Douglas | 1949–1967 | 2 | Illinois | Democratic | 1892–1976 |
| Stephen A. Douglas | 1847–1861 | 2 | Illinois | Democratic | 1813–1861 |
| Sheridan Downey | 1939–1950 | 3 | California | Democratic | 1884–1961 |
| Solomon W. Downs | 1847–1853 | 2 | Louisiana | Democratic | 1801–1854 |
| Wall Doxey | 1941–1943 | 2 | Mississippi | Democratic | 1892–1962 |
| Charles D. Drake | 1867–1870 | 3 | Missouri | Republican | 1811–1892 |
| Irving W. Drew | 1918 | 3 | New Hampshire | Republican | 1845–1922 |
| John F. Dryden | 1902–1907 | 2 | New Jersey | Republican | 1839–1911 |
| Henry A. du Pont | 1895–1896 1906–1917 | 1 | Delaware | Republican | 1838–1926 |
| T. Coleman du Pont | 1921–1922 1925–1928 | 1, 2 | Delaware | Republican | 1863–1930 |
| Fred Dubois | 1891–1896 1896–1897 1901–1907 | 2, 3 | Idaho | Republican Silver Republican Democratic | 1851–1930 |
| Charles E. Dudley | 1829–1833 | 1 | New York | Democratic | 1780–1841 |
| James H. Duff | 1951–1957 | 3 | Pennsylvania | Republican | 1883–1969 |
| F. Ryan Duffy | 1933–1939 | 3 | Wisconsin | Democratic | 1888–1979 |
| John Foster Dulles | 1949 | 3 | New York | Republican | 1888–1959 |
| David Durenberger | 1978–1995 | 1 | Minnesota | Republican | 1934–2023 |
| Charles Durkee | 1855–1861 | 3 | Wisconsin | Republican | 1805–1870 |
| John A. Durkin | 1975–1980 | 3 | New Hampshire | Democratic | 1936–2012 |
| Henry Dworshak | 1946–1949 1949–1962 | 2 | Idaho | Republican | 1894–1962 |
| Thomas Eagleton | 1969–1987 | 3 | Missouri | Democratic | 1929–2007 |
| Joseph H. Earle | 1897 | 3 | South Carolina | Democratic | 1847–1897 |
| John Porter East | 1981–1986 | 3 | North Carolina | Republican | 1931–1986 |
| James Eastland | 1941 1943–1978 | 2 | Mississippi | Democratic | 1904–1986 |
| John Eaton | 1818–1821 1821–1829 | 1 | Tennessee | Democratic-Republican | 1790–1856 |
| William W. Eaton | 1875–1881 | 1 | Connecticut | Democratic | 1816–1898 |
| Zales Ecton | 1947–1953 | 1 | Montana | Republican | 1898–1961 |
| Walter Evans Edge | 1919–1929 | 3 | New Jersey | Republican | 1873–1956 |
| Alonzo J. Edgerton | 1881 | 2 | Minnesota | Republican | 1827–1896 |
| J. Howard Edmondson | 1963–1964 | 2 | Oklahoma | Democratic | 1925–1971 |
| George F. Edmunds | 1866–1891 | 1 | Vermont | Republican | 1828–1919 |
| Edward I. Edwards | 1923–1929 | 1 | New Jersey | Democratic | 1863–1931 |
| Elaine Edwards | 1972 | 2 | Louisiana | Democratic | 1929–2018 |
| Henry W. Edwards | 1823–1827 | 1 | Connecticut | Democratic | 1779–1847 |
| John Edwards | 1792–1795 | 3 | Kentucky | Democratic-Republican | 1748–1837 |
| John Edwards | 1999–2005 | 3 | North Carolina | Democratic | 1953–present |
| Ninian Edwards | 1818–1824 | 3 | Illinois | Democratic-Republican | 1775–1833 |
| Davis Elkins | 1911 1919–1925 | 2 | West Virginia | Republican | 1876–1959 |
| Stephen Benton Elkins | 1895–1911 | 2 | West Virginia | Republican | 1841–1911 |
| Allen J. Ellender | 1937–1972 | 2 | Louisiana | Democratic | 1890–1972 |
| Christopher Ellery | 1801–1805 | 2 | Rhode Island | Democratic-Republican | 1769–1840 |
| John Elliott | 1819–1825 | 3 | Georgia | Democratic-Republican | 1773–1827 |
| Powhatan Ellis | 1825–1826 1827–1832 | 1 | Mississippi | Democratic | 1790–1863 |
| Oliver Ellsworth | 1789–1796 | 1 | Connecticut | Federalist | 1745–1807 |
| Jonathan Elmer | 1789–1791 | 1 | New Jersey | Federalist | 1745–1817 |
| Franklin H. Elmore | 1850 | 2 | South Carolina | Democratic | 1799–1850 |
| Clair Engle | 1959–1964 | 1 | California | Democratic | 1911–1964 |
| James E. English | 1875–1876 | 3 | Connecticut | Democratic | 1812–1890 |
| John Ensign | 2001–2011 | 1 | Nevada | Republican | 1958–present |
| Mike Enzi | 1997–2021 | 2 | Wyoming | Republican | 1944–2021 |
| John Wayles Eppes | 1817–1819 | 2 | Virginia | Democratic-Republican | 1773–1823 |
| John E. Erickson | 1933–1934 | 2 | Montana | Democratic | 1863–1946 |
| Richard P. Ernst | 1921–1927 | 3 | Kentucky | Republican | 1858–1934 |
| Sam Ervin | 1954–1974 | 3 | North Carolina | Democratic | 1896–1985 |
| James B. Eustis | 1876–1879 1885–1891 | 3 | Louisiana | Democratic | 1834–1899 |
| Daniel J. Evans | 1983–1989 | 1 | Washington | Republican | 1925–2024 |
| George Evans | 1841–1847 | 2 | Maine | Whig | 1797–1867 |
| Josiah J. Evans | 1853–1858 | 2 | South Carolina | Democratic | 1786–1858 |
| William M. Evarts | 1885–1891 | 3 | New York | Republican | 1818–1901 |
| Edward Everett | 1853–1854 | 2 | Massachusetts | Whig | 1794–1865 |
| Thomas Ewing | 1831–1837 1850–1851 | 1, 3 | Ohio | National Republican Whig | 1789–1871 |
| William Lee D. Ewing | 1835–1837 | 3 | Illinois | Democratic | 1795–1846 |
| J. James Exon | 1979–1997 | 2 | Nebraska | Democratic | 1921–2005 |
| James Graham Fair | 1881–1887 | 1 | Nevada | Democratic | 1831–1894 |
| Charles W. Fairbanks | 1897–1905 | 3 | Indiana | Republican | 1852–1918 |
| Lauch Faircloth | 1993–1999 | 3 | North Carolina | Republican | 1928–2023 |
| John Fairfield | 1843–1847 | 1 | Maine | Democratic | 1797–1847 |
| Albert B. Fall | 1912–1921 | 2 | New Mexico | Republican | 1861–1944 |
| Paul Fannin | 1965–1977 | 1 | Arizona | Republican | 1907–2002 |
| James T. Farley | 1879–1885 | 3 | California | Democratic | 1829–1886 |
| Charles B. Farwell | 1887–1891 | 3 | Illinois | Republican | 1823–1903 |
| Nathan A. Farwell | 1864–1865 | 1 | Maine | Republican | 1812–1893 |
| Charles James Faulkner | 1887–1899 | 1 | West Virginia | Democratic | 1847–1929 |
| William C. Feazel | 1948 | 3 | Louisiana | Democratic | 1895–1965 |
| Russ Feingold | 1993–2011 | 3 | Wisconsin | Democratic | 1953–present |
| Dianne Feinstein | 1992–2023 | 1 | California | Democratic | 1933–2023 |
| Alpheus Felch | 1847–1853 | 2 | Michigan | Democratic | 1804–1896 |
| Charles N. Felton | 1891–1893 | 1 | California | Republican | 1832–1914 |
| Rebecca Latimer Felton | 1922 | 3 | Georgia | Democratic | 1835–1930 |
| James Fenner | 1805–1807 | 2 | Rhode Island | Democratic-Republican | 1771–1846 |
| Reuben Fenton | 1869–1872 1872–1875 | 1 | New York | Republican Liberal Republican | 1819–1885 |
| Homer S. Ferguson | 1943–1955 | 2 | Michigan | Republican | 1889–1982 |
| Bert M. Fernald | 1916–1926 | 2 | Maine | Republican | 1858–1926 |
| Woodbridge N. Ferris | 1923–1928 | 1 | Michigan | Democratic | 1853–1928 |
| Orris S. Ferry | 1867–1872 1872–1875 1875 | 3 | Connecticut | Republican Liberal Republican Republican | 1823–1875 |
| Thomas W. Ferry | 1871–1883 | 2 | Michigan | Republican | 1827–1896 |
| Simeon D. Fess | 1923–1935 | 1 | Ohio | Republican | 1861–1936 |
| William P. Fessenden | 1854–1856 1856–1864 1865–1869 | 2 | Maine | Whig Republican Republican | 1806–1869 |
| William Few | 1789–1793 | 1 | Georgia | Democratic-Republican | 1748–1828 |
| Richard Stockton Field | 1862–1863 | 1 | New Jersey | Republican | 1803–1870 |
| William Findlay | 1821–1824 1824–1827 | 1 | Pennsylvania | Democratic-Republican Democratic | 1768–1846 |
| Hamilton Fish | 1851–1856 1856–1857 | 1 | New York | Whig Republican | 1808–1893 |
| James Fisk | 1817–1818 | 3 | Vermont | Democratic-Republican | 1763–1844 |
| Graham N. Fitch | 1857–1861 | 3 | Indiana | Democratic | 1809–1892 |
| Peter Fitzgerald | 1999–2005 | 3 | Illinois | Republican | 1960–present |
| Thomas Fitzgerald | 1848–1849 | 1 | Michigan | Democratic | 1796–1855 |
| Benjamin Fitzpatrick | 1848–1849 1853–1855 1855–1861 | 2, 3 | Alabama | Democratic | 1802–1869 |
| Jeff Flake | 2013–2019 | 1 | Arizona | Republican | 1962–present |
| James W. Flanagan | 1870–1875 | 1 | Texas | Republican | 1805–1887 |
| Ralph Flanders | 1946–1959 | 1 | Vermont | Republican | 1880–1970 |
| Duncan U. Fletcher | 1909–1936 | 3 | Florida | Democratic | 1859–1936 |
| Frank Putnam Flint | 1905–1911 | 1 | California | Republican | 1862–1929 |
| George G. Fogg | 1866–1867 | 3 | New Hampshire | Republican | 1813–1881 |
| Hiram Fong | 1959–1977 | 1 | Hawaii | Republican | 1906–2004 |
| Samuel A. Foot | 1827–1833 | 1 | Connecticut | National Republican | 1780–1846 |
| Solomon Foot | 1851–1856 1856–1866 | 1 | Vermont | Whig Republican | 1802–1866 |
| Henry S. Foote | 1847–1852 | 2 | Mississippi | Democratic | 1804–1880 |
| Joseph B. Foraker | 1897–1909 | 3 | Ohio | Republican | 1846–1917 |
| Wendell Ford | 1974–1999 | 3 | Kentucky | Democratic | 1924–2015 |
| John Forsyth | 1818–1819 1829–1834 | 2, 3 | Georgia | Democratic-Republican Democratic | 1780–1841 |
| Addison G. Foster | 1899–1905 | 1 | Washington | Republican | 1837–1917 |
| Dwight Foster | 1800–1803 | 2 | Massachusetts | Federalist | 1757–1823 |
| Ephraim H. Foster | 1838–1839 1843–1845 | 1 | Tennessee | Whig | 1794–1854 |
| Henry A. Foster | 1844–1845 | 3 | New York | Democratic | 1800–1889 |
| Lafayette S. Foster | 1855–1856 1856–1867 | 3 | Connecticut | Whig Republican | 1806–1880 |
| Murphy J. Foster | 1901–1913 | 2 | Louisiana | Democratic | 1849–1921 |
| Theodore Foster | 1790–1801 1801–1803 | 1 | Rhode Island | Federalist Democratic-Republican | 1752–1828 |
| Joseph S. Fowler | 1866–1871 | 2 | Tennessee | Republican | 1820–1902 |
| Wyche Fowler | 1987–1993 | 3 | Georgia | Democratic | 1940–present |
| Sheila Frahm | 1996 | 3 | Kansas | Republican | 1945–present |
| Joseph I. France | 1917–1923 | 1 | Maryland | Republican | 1873–1939 |
| John Brown Francis | 1844–1845 | 1 | Rhode Island | Law and Order | 1791–1864 |
| Al Franken | 2009–2018 | 2 | Minnesota | Democratic | 1951–present |
| Jesse Franklin | 1799–1805 1807–1813 | 2, 3 | North Carolina | Democratic-Republican | 1760–1823 |
| James B. Frazier | 1905–1911 | 1 | Tennessee | Democratic | 1856–1937 |
| Lynn Frazier | 1923–1941 | 1 | North Dakota | Republican | 1874–1947 |
| J. Allen Frear Jr. | 1949–1961 | 2 | Delaware | Democratic | 1903–1993 |
| Frederick Frelinghuysen | 1793–1796 | 1 | New Jersey | Federalist | 1753–1804 |
| Frederick T. Frelinghuysen | 1866–1869 1871–1877 | 1, 2 | New Jersey | Republican | 1817–1885 |
| Joseph S. Frelinghuysen Sr. | 1917–1923 | 1 | New Jersey | Republican | 1869–1948 |
| Theodore Frelinghuysen | 1829–1835 | 2 | New Jersey | National Republican | 1787–1862 |
| John C. Frémont | 1850–1851 | 1 | California | Republican | 1813–1890 |
| Bill Frist | 1995–2007 | 1 | Tennessee | Republican | 1952–present |
| Eligius Fromentin | 1813–1819 | 3 | Louisiana | Democratic-Republican | 1767–1822 |
| William P. Frye | 1881–1911 | 2 | Maine | Republican | 1830–1911 |
| J. William Fulbright | 1945–1974 | 3 | Arkansas | Democratic | 1905–1995 |
| Charles William Fulton | 1903–1909 | 3 | Oregon | Republican | 1853–1918 |
| William S. Fulton | 1836–1844 | 2 | Arkansas | Democratic | 1795–1844 |
| John Gaillard | 1805–1824 1824–1826 | 3 | South Carolina | Democratic-Republican Democratic | 1765–1826 |
| Jacob Harold Gallinger | 1891–1918 | 3 | New Hampshire | Republican | 1837–1918 |
| Robert J. Gamble | 1901–1913 | 2 | South Dakota | Republican | 1851–1924 |
| David H. Gambrell | 1971–1972 | 2 | Georgia | Democratic | 1929–2021 |
| Cory Gardner | 2015–2021 | 2 | Colorado | Republican | 1974–present |
| Obadiah Gardner | 1911–1913 | 2 | Maine | Democratic | 1852–1938 |
| Augustus Hill Garland | 1877–1885 | 2 | Arkansas | Democratic | 1832–1899 |
| Jake Garn | 1974–1993 | 3 | Utah | Republican | 1932–present |
| Frank B. Gary | 1908–1909 | 3 | South Carolina | Democratic | 1860–1922 |
| Edward James Gay | 1918–1921 | 3 | Louisiana | Democratic | 1878–1952 |
| John H. Gear | 1895–1900 | 2 | Iowa | Republican | 1825–1900 |
| John M. Gearin | 1905–1907 | 2 | Oregon | Democratic | 1851–1930 |
| James Z. George | 1881–1897 | 1 | Mississippi | Democratic | 1826–1897 |
| Walter F. George | 1922–1957 | 3 | Georgia | Democratic | 1878–1957 |
| Obadiah German | 1809–1815 | 1 | New York | Democratic-Republican | 1766–1842 |
| Peter G. Gerry | 1917–1929 1935–1947 | 1 | Rhode Island | Democratic | 1879–1957 |
| Henry S. Geyer | 1851–1855 1855–1857 | 1 | Missouri | Whig Democratic | 1790–1859 |
| Charles Hopper Gibson | 1891–1897 | 3 | Maryland | Democratic | 1842–1900 |
| Ernest W. Gibson Jr. | 1940–1941 | 3 | Vermont | Republican | 1901–1969 |
| Ernest Willard Gibson | 1933–1940 | 3 | Vermont | Republican | 1872–1940 |
| Paris Gibson | 1901–1905 | 1 | Montana | Democratic | 1830–1920 |
| Randall L. Gibson | 1883–1892 | 2 | Louisiana | Democratic | 1832–1892 |
| Abijah Gilbert | 1869–1875 | 1 | Florida | Republican | 1806–1881 |
| William Branch Giles | 1804–1815 | 1, 2 | Virginia | Democratic-Republican | 1762–1830 |
| Frederick H. Gillett | 1925–1931 | 2 | Massachusetts | Republican | 1851–1935 |
| Francis Gillette | 1854–1855 | 2 | Connecticut | Free Soil | 1807–1879 |
| Guy Gillette | 1936–1945 1949–1955 | 2, 3 | Iowa | Democratic | 1879–1973 |
| Nicholas Gilman | 1805–1814 | 2 | New Hampshire | Democratic-Republican | 1755–1814 |
| Carter Glass | 1920–1946 | 2 | Virginia | Democratic | 1858–1946 |
| John Glenn | 1974–1999 | 3 | Ohio | Democratic | 1921–2016 |
| Otis F. Glenn | 1928–1933 | 3 | Illinois | Republican | 1879–1959 |
| Guy D. Goff | 1925–1931 | 2 | West Virginia | Republican | 1866–1933 |
| Nathan Goff Jr. | 1913–1919 | 2 | West Virginia | Republican | 1843–1920 |
| Phillips Lee Goldsborough | 1929–1935 | 1 | Maryland | Republican | 1865–1946 |
| Robert Henry Goldsborough | 1813–1819 1835–1836 | 3 | Maryland | Federalist National Republican | 1779–1836 |
| George Goldthwaite | 1871–1877 | 2 | Alabama | Democratic | 1809–1879 |
| Barry Goldwater | 1953–1965 1969–1987 | 1, 3 | Arizona | Republican | 1909–1998 |
| Charles Goodell | 1968–1971 | 1 | New York | Republican | 1926–1987 |
| Benjamin Goodhue | 1796–1800 | 1 | Massachusetts | Federalist | 1748–1814 |
| Frank R. Gooding | 1921–1928 | 3 | Idaho | Republican | 1859–1928 |
| Chauncey Goodrich | 1807–1813 | 3 | Connecticut | Federalist | 1759–1815 |
| Carte Goodwin | 2010 | 1 | West Virginia | Democratic | 1974–present |
| James Gordon | 1909–1910 | 2 | Mississippi | Democratic | 1833–1912 |
| John B. Gordon | 1873–1880 1891–1897 | 3 | Georgia | Democratic | 1832–1904 |
| Al Gore | 1985–1993 | 2 | Tennessee | Democratic | 1948–present |
| Albert Gore Sr. | 1953–1971 | 1 | Tennessee | Democratic | 1907–1998 |
| Christopher Gore | 1813–1816 | 1 | Massachusetts | Federalist | 1758–1827 |
| Thomas Gore | 1907–1921 1931–1937 | 2, 3 | Oklahoma | Democratic | 1870–1949 |
| Arthur Pue Gorman | 1881–1899 1903–1906 | 1, 3 | Maryland | Democratic | 1839–1906 |
| Slade Gorton | 1981–1987 1989–2001 | 3 1 | Washington | Republican | 1928–2020 |
| Charles C. Gossett | 1945–1946 | 2 | Idaho | Democratic | 1888–1974 |
| Arthur R. Gould | 1926–1931 | 2 | Maine | Republican | 1857–1946 |
| Bob Graham | 1987–2005 | 3 | Florida | Democratic | 1936–2024 |
| Frank Porter Graham | 1949–1950 | 2 | North Carolina | Democratic | 1886–1972 |
| William Alexander Graham | 1840–1843 | 3 | North Carolina | Whig | 1804–1875 |
| Phil Gramm | 1985–2002 | 3 | Texas | Republican | 1942–present |
| Elijah S. Grammer | 1932–1933 | 3 | Washington | Republican | 1868–1936 |
| Rod Grams | 1995–2001 | 1 | Minnesota | Republican | 1948–2013 |
| Mike Gravel | 1969–1981 | 3 | Alaska | Democratic | 1930–2021 |
| Dixie Bibb Graves | 1937–1938 | 3 | Alabama | Democratic | 1882–1965 |
| George Gray | 1885–1899 | 1 | Delaware | Democratic | 1840–1925 |
| William Grayson | 1789–1790 | 1 | Virginia | Democratic-Republican | 1740–1790 |
| James S. Green | 1857–1861 | 3 | Missouri | Democratic | 1817–1870 |
| Theodore F. Green | 1937–1961 | 2 | Rhode Island | Democratic | 1867–1966 |
| Albert C. Greene | 1845–1851 | 1 | Rhode Island | Whig | 1792–1863 |
| Frank L. Greene | 1923–1930 | 1 | Vermont | Republican | 1870–1930 |
| Ray Greene | 1797–1801 | 3 | Rhode Island | Federalist | 1765–1849 |
| Andrew Gregg | 1807–1813 | 2 | Pennsylvania | Democratic-Republican | 1755–1835 |
| Judd Gregg | 1993–2011 | 3 | New Hampshire | Republican | 1947–present |
| Robert P. Griffin | 1966–1979 | 2 | Michigan | Republican | 1923–2015 |
| James W. Grimes | 1859–1869 | 2 | Iowa | Republican | 1816–1872 |
| Dwight Griswold | 1952–1954 | 2 | Nebraska | Republican | 1893–1954 |
| Stanley Griswold | 1809 | 3 | Ohio | Democratic-Republican | 1763–1815 |
| Asle Gronna | 1911–1921 | 3 | North Dakota | Republican | 1858–1922 |
| James Black Groome | 1879–1885 | 3 | Maryland | Democratic | 1838–1893 |
| La Fayette Grover | 1877–1883 | 3 | Oregon | Democratic | 1823–1911 |
| Ernest Gruening | 1959–1969 | 1 | Alaska | Democratic | 1887–1974 |
| Felix Grundy | 1829–1838 1839–1840 | 1 | Tennessee | Democratic | 1775–1840 |
| Joseph R. Grundy | 1929–1930 | 3 | Pennsylvania | Republican | 1863–1961 |
| Joseph F. Guffey | 1935–1947 | 1 | Pennsylvania | Democratic | 1870–1959 |
| Simon Guggenheim | 1907–1913 | 2 | Colorado | Republican | 1867–1941 |
| Walter Guion | 1918 | 3 | Louisiana | Democratic | 1849–1927 |
| James Gunn | 1789–1797 1797–1801 | 3 | Georgia | Democratic-Republican Federalist | 1753–1801 |
| Edward Gurney | 1969–1974 | 3 | Florida | Republican | 1914–1996 |
| John Chandler Gurney | 1939–1951 | 3 | South Dakota | Republican | 1896–1985 |
| James Guthrie | 1865–1868 | 2 | Kentucky | Democratic | 1792–1869 |
| William M. Gwin | 1850–1855 1857–1861 | 3 | California | Democratic | 1805–1885 |
| Kay Hagan | 2009–2015 | 2 | North Carolina | Democratic | 1953–2019 |
| Chuck Hagel | 1997–2009 | 3 | Nebraska | Republican | 1946–present |
| John S. Hager | 1873–1875 | 1 | California | Democratic | 1818–1890 |
| Eugene Hale | 1881–1911 | 1 | Maine | Republican | 1836–1918 |
| Frederick Hale | 1917–1941 | 1 | Maine | Republican | 1874–1963 |
| John P. Hale | 1847–1848 1848–1853 1855–1856 1856–1865 | 1 | New Hampshire | Independent Democrat Free Soil Free Soil Republican | 1806–1873 |
| Wilton E. Hall | 1944–1945 | 2 | South Carolina | Democratic | 1901–1980 |
| Morgan C. Hamilton | 1870–1873 1873–1875 1875–1877 | 2 | Texas | Republican Liberal Republican Republican | 1809–1893 |
| William Thomas Hamilton | 1869–1875 | 1 | Maryland | Democratic | 1820–1888 |
| Hannibal Hamlin | 1848–1856 1856–1857 1857–1861 1869–1881 | 3 | Maine | Democratic Republican Republican Republican | 1809–1891 |
| James Henry Hammond | 1857–1860 | 3 | South Carolina | Democratic | 1807–1864 |
| Wade Hampton III | 1879–1891 | 3 | South Carolina | Democratic | 1818–1902 |
| Mark Hanna | 1897–1904 | 1 | Ohio | Republican | 1837–1904 |
| Robert Hanna | 1831–1832 | 1 | Indiana | National Republican | 1786–1858 |
| Edward A. Hannegan | 1843–1849 | 3 | Indiana | Democratic | 1807–1859 |
| Henry C. Hansbrough | 1891–1909 | 3 | North Dakota | Republican | 1848–1933 |
| Clifford Hansen | 1967–1978 | 2 | Wyoming | Republican | 1912–2009 |
| Alexander Contee Hanson | 1816–1819 | 1 | Maryland | Federalist | 1786–1819 |
| Martin D. Hardin | 1816–1817 | 2 | Kentucky | Federalist | 1780–1823 |
| Benjamin F. Harding | 1862–1865 | 2 | Oregon | Democratic | 1823–1899 |
| Warren G. Harding | 1915–1921 | 3 | Ohio | Republican | 1865–1923 |
| Thomas W. Hardwick | 1914–1919 | 2 | Georgia | Democratic | 1872–1944 |
| Tom Harkin | 1985–2015 | 2 | Iowa | Democratic | 1939–present |
| James Harlan | 1855–1857 1857–1865 1867–1873 | 3 | Iowa | Free Soil Republican Republican | 1820–1899 |
| Robert Goodloe Harper | 1816 | 1 | Maryland | Federalist | 1765–1825 |
| William Harper | 1826 | 3 | South Carolina | Democratic | 1790–1847 |
| John W. Harreld | 1921–1927 | 3 | Oklahoma | Republican | 1872–1950 |
| Fred R. Harris | 1964–1973 | 2 | Oklahoma | Democratic | 1930–2024 |
| Ira Harris | 1861–1867 | 3 | New York | Republican | 1802–1875 |
| Isham G. Harris | 1877–1897 | 2 | Tennessee | Democratic | 1818–1897 |
| John S. Harris | 1868–1871 | 2 | Louisiana | Republican | 1825–1906 |
| Kamala Harris | 2017–2021 | 3 | California | Democratic | 1964–present |
| William Alexander Harris | 1897–1903 | 3 | Kansas | Populist | 1841–1909 |
| William J. Harris | 1919–1932 | 2 | Georgia | Democratic | 1868–1932 |
| Benjamin Harrison | 1881–1887 | 1 | Indiana | Republican | 1833–1901 |
| Pat Harrison | 1919–1941 | 2 | Mississippi | Democratic | 1881–1941 |
| William Henry Harrison | 1825–1828 | 3 | Ohio | National Republican | 1773–1841 |
| Gary Hart | 1975–1987 | 3 | Colorado | Democratic | 1936–present |
| Philip Hart | 1959–1976 | 1 | Michigan | Democratic | 1912–1976 |
| Thomas C. Hart | 1945–1946 | 1 | Connecticut | Republican | 1877–1971 |
| Vance Hartke | 1959–1977 | 1 | Indiana | Democratic | 1919–2003 |
| James M. Harvey | 1874–1877 | 2 | Kansas | Republican | 1833–1894 |
| Floyd Haskell | 1973–1979 | 2 | Colorado | Democratic | 1916–1998 |
| Daniel O. Hastings | 1928–1937 | 2 | Delaware | Republican | 1874–1966 |
| Carl Hatch | 1933–1949 | 2 | New Mexico | Democratic | 1889–1963 |
| Orrin Hatch | 1977–2019 | 1 | Utah | Republican | 1934–2022 |
| Henry D. Hatfield | 1929–1935 | 1 | West Virginia | Republican | 1875–1962 |
| Mark Hatfield | 1967–1997 | 2 | Oregon | Republican | 1922–2011 |
| Paul G. Hatfield | 1978 | 2 | Montana | Democratic | 1928–2000 |
| William Hathaway | 1973–1979 | 2 | Maine | Democratic | 1924–2013 |
| Henry P. Haun | 1859–1860 | 1 | California | Democratic | 1815–1860 |
| Harry B. Hawes | 1926–1933 | 3 | Missouri | Democratic | 1869–1947 |
| Albert W. Hawkes | 1943–1949 | 2 | New Jersey | Republican | 1878–1971 |
| Benjamin Hawkins | 1789–1791 1791–1795 | 3 | North Carolina | Federalist Democratic-Republican | 1754–1816 |
| Paula Hawkins | 1981–1987 | 3 | Florida | Republican | 1927–2009 |
| Joseph Roswell Hawley | 1881–1905 | 1 | Connecticut | Republican | 1826–1905 |
| S. I. Hayakawa | 1977–1983 | 1 | California | Republican | 1906–1992 |
| Carl Hayden | 1927–1969 | 3 | Arizona | Democratic | 1877–1972 |
| Arthur P. Hayne | 1858 | 2 | South Carolina | Democratic | 1788–1867 |
| Robert Y. Hayne | 1823–1824 1824–1831 1831–1832 | 2 | South Carolina | Democratic-Republican Democratic Nullifier | 1791–1839 |
| Monroe Hayward | 1899 | 1 | Nebraska | Republican | 1840–1899 |
| William Henry Haywood Jr. | 1843–1846 | 3 | North Carolina | Democratic | 1801–1852 |
| George Hearst | 1886 1887–1891 | 1 | California | Democratic | 1820–1891 |
| Felix Hebert | 1929–1935 | 1 | Rhode Island | Republican | 1874–1969 |
| Chic Hecht | 1983–1989 | 1 | Nevada | Republican | 1928–2006 |
| Howell Heflin | 1979–1997 | 2 | Alabama | Democratic | 1921–2005 |
| James Thomas Heflin | 1920–1931 | 2 | Alabama | Democratic | 1869–1951 |
| John Heinz | 1977–1991 | 1 | Pennsylvania | Republican | 1938–1991 |
| John N. Heiskell | 1913 | 2 | Arkansas | Democratic | 1872–1972 |
| Henry Heitfeld | 1897–1901 1901–1903 | 3 | Idaho | Populist Democratic | 1859–1938 |
| Heidi Heitkamp | 2013–2019 | 1 | North Dakota | Democratic | 1955–present |
| Dean Heller | 2011–2019 | 1 | Nevada | Republican | 1960–present |
| Jesse Helms | 1973–2003 | 2 | North Carolina | Republican | 1921–2008 |
| George Helmy | 2024 | 1 | New Jersey | Democratic | 1979–present |
| James A. Hemenway | 1905–1909 | 3 | Indiana | Republican | 1860–1923 |
| John Hemphill | 1859–1861 | 2 | Texas | Democratic | 1803–1862 |
| Charles Henderson | 1918–1921 | 3 | Nevada | Democratic | 1873–1954 |
| James Pinckney Henderson | 1857–1858 | 1 | Texas | Democratic | 1808–1858 |
| John Henderson | 1839–1845 | 1 | Mississippi | Whig | 1797–1857 |
| John B. Henderson | 1862–1865 1865–1869 | 1 | Missouri | Union Republican | 1826–1913 |
| Thomas A. Hendricks | 1863–1869 | 1 | Indiana | Democratic | 1819–1885 |
| William Hendricks | 1825–1837 | 3 | Indiana | National Republican | 1782–1850 |
| Robert C. Hendrickson | 1949–1955 | 2 | New Jersey | Republican | 1898–1964 |
| Thomas C. Hennings Jr. | 1951–1960 | 3 | Missouri | Democratic | 1903–1960 |
| John Henry | 1789–1797 | 3 | Maryland | Federalist | 1750–1798 |
| Frank Hereford | 1877–1881 | 1 | West Virginia | Democratic | 1825–1891 |
| Clyde L. Herring | 1937–1943 | 2 | Iowa | Democratic | 1879–1945 |
| Weldon Brinton Heyburn | 1903–1912 | 3 | Idaho | Republican | 1852–1912 |
| Bourke B. Hickenlooper | 1945–1969 | 3 | Iowa | Republican | 1896–1971 |
| John J. Hickey | 1961–1962 | 2 | Wyoming | Democratic | 1911–1970 |
| Thomas Holliday Hicks | 1862–1865 | 3 | Maryland | Unconditional Union | 1798–1865 |
| Anthony Higgins | 1889–1895 | 3 | Delaware | Republican | 1840–1912 |
| Benjamin Harvey Hill | 1877–1882 | 2 | Georgia | Democratic | 1823–1882 |
| David B. Hill | 1892–1897 | 3 | New York | Democratic | 1843–1910 |
| Isaac Hill | 1831–1836 | 3 | New Hampshire | Democratic | 1789–1851 |
| J. Lister Hill | 1938–1969 | 3 | Alabama | Democratic | 1894–1984 |
| Joshua Hill | 1868–1873 | 3 | Georgia | Republican | 1812–1891 |
| Nathaniel P. Hill | 1879–1885 | 3 | Colorado | Republican | 1832–1900 |
| William Luther Hill | 1936 | 3 | Florida | Democratic | 1873–1951 |
| James Hillhouse | 1796–1810 | 1 | Connecticut | Federalist | 1754–1832 |
| William Hindman | 1800–1801 | 3 | Maryland | Federalist | 1743–1822 |
| Frank Hiscock | 1887–1893 | 1 | New York | Republican | 1834–1914 |
| Gilbert Hitchcock | 1911–1923 | 1 | Nebraska | Democratic | 1859–1934 |
| Herbert E. Hitchcock | 1936–1938 | 3 | South Dakota | Democratic | 1867–1958 |
| Phineas Hitchcock | 1871–1877 | 2 | Nebraska | Republican | 1831–1881 |
| George Frisbie Hoar | 1877–1904 | 2 | Massachusetts | Republican | 1826–1904 |
| John Sloss Hobart | 1798 | 1 | New York | Federalist | 1738–1805 |
| John D. Hoblitzell Jr. | 1958 | 2 | West Virginia | Republican | 1912–1962 |
| Kaneaster Hodges Jr. | 1977–1979 | 2 | Arkansas | Democratic | 1938–2022 |
| Clyde R. Hoey | 1945–1954 | 3 | North Carolina | Democratic | 1877–1954 |
| Spessard Holland | 1946–1971 | 1 | Florida | Democratic | 1892–1971 |
| Fritz Hollings | 1966–2005 | 3 | South Carolina | Democratic | 1922–2019 |
| Henry F. Hollis | 1913–1919 | 2 | New Hampshire | Democratic | 1869–1949 |
| Rufus C. Holman | 1939–1945 | 2 | Oregon | Republican | 1877–1959 |
| David Holmes | 1820–1825 | 1 | Mississippi | Democratic-Republican | 1769–1832 |
| John Holmes | 1820–1824 1824–1827 1829–1833 | 1 | Maine | Democratic-Republican National Republican National Republican | 1773–1843 |
| Rush Holt Sr. | 1935–1941 | 1 | West Virginia | Democratic | 1905–1955 |
| Albert J. Hopkins | 1903–1909 | 3 | Illinois | Republican | 1846–1922 |
| Outerbridge Horsey | 1810–1821 | 1 | Delaware | Federalist | 1777–1842 |
| Andrew Jackson Houston | 1941 | 2 | Texas | Democratic | 1854–1941 |
| George S. Houston | 1879 | 3 | Alabama | Democratic | 1811–1879 |
| Sam Houston | 1846–1855 1855–1859 | 2 | Texas | Democratic American | 1793–1863 |
| Guy V. Howard | 1936–1937 | 2 | Minnesota | Republican | 1879–1954 |
| Jacob M. Howard | 1862–1871 | 2 | Michigan | Republican | 1805–1871 |
| John Eager Howard | 1796–1803 | 1 | Maryland | Federalist | 1752–1827 |
| Timothy O. Howe | 1861–1879 | 3 | Wisconsin | Republican | 1816–1883 |
| James B. Howell | 1870–1871 | 2 | Iowa | Republican | 1816–1880 |
| Jeremiah B. Howell | 1811–1817 | 2 | Rhode Island | Democratic-Republican | 1771–1822 |
| Robert B. Howell | 1923–1933 | 1 | Nebraska | Republican | 1864–1933 |
| Benjamin Howland | 1804–1809 | 1 | Rhode Island | Democratic-Republican | 1755–1821 |
| Roman Hruska | 1954–1976 | 2 | Nebraska | Republican | 1904–1999 |
| Henry Hubbard | 1835–1841 | 2 | New Hampshire | Democratic | 1784–1857 |
| Walter Dee Huddleston | 1973–1985 | 2 | Kentucky | Democratic | 1926–2018 |
| James W. Huffman | 1945–1946 | 1 | Ohio | Democratic | 1894–1980 |
| Daniel Elliott Huger | 1843–1845 | 2 | South Carolina | Democratic | 1779–1854 |
| Charles J. Hughes Jr. | 1909–1911 | 3 | Colorado | Democratic | 1853–1911 |
| Harold Hughes | 1969–1975 | 3 | Iowa | Democratic | 1922–1996 |
| James H. Hughes | 1937–1943 | 2 | Delaware | Democratic | 1867–1953 |
| William Hughes | 1913–1918 | 2 | New Jersey | Democratic | 1872–1918 |
| Cordell Hull | 1931–1933 | 2 | Tennessee | Democratic | 1871–1955 |
| Gordon J. Humphrey | 1979–1990 | 2 | New Hampshire | Republican | 1940–present |
| Hubert Humphrey | 1949–1964 1971–1978 | 1, 2 | Minnesota | Democratic | 1911–1978 |
| Muriel Humphrey | 1978 | 1 | Minnesota | Democratic | 1912–1998 |
| Robert Humphreys | 1956 | 2 | Kentucky | Democratic | 1893–1977 |
| Lester C. Hunt | 1949–1954 | 2 | Wyoming | Democratic | 1892–1954 |
| John Hunter | 1796–1798 | 2 | South Carolina | Democratic-Republican | 1750–1802 |
| Richard C. Hunter | 1934–1935 | 1 | Nebraska | Democratic | 1884–1941 |
| Robert M. T. Hunter | 1847–1861 | 2 | Virginia | Democratic | 1809–1887 |
| William Hunter | 1811–1821 | 1 | Rhode Island | Federalist | 1774–1849 |
| Jabez W. Huntington | 1840–1847 | 1 | Connecticut | Whig | 1788–1847 |
| Eppa Hunton | 1892–1895 | 2 | Virginia | Democratic | 1822–1908 |
| Paul O. Husting | 1915–1917 | 3 | Wisconsin | Democratic | 1866–1917 |
| Tim Hutchinson | 1997–2003 | 2 | Arkansas | Republican | 1949–present |
| Kay Bailey Hutchison | 1993–2013 | 1 | Texas | Republican | 1943–present |
| John James Ingalls | 1873–1891 | 3 | Kansas | Republican | 1833–1900 |
| Jim Inhofe | 1994–2023 | 2 | Oklahoma | Republican | 1934–2024 |
| Daniel Inouye | 1963–2012 | 3 | Hawaii | Democratic | 1924–2012 |
| John L. M. Irby | 1891–1897 | 3 | South Carolina | Democratic | 1854–1900 |
| James Iredell Jr. | 1828–1831 | 3 | North Carolina | Democratic | 1788–1853 |
| Johnny Isakson | 2005–2019 | 3 | Georgia | Republican | 1944–2021 |
| Alfred Iverson Sr. | 1855–1861 | 3 | Georgia | Democratic | 1798–1873 |
| Irving Ives | 1947–1959 | 1 | New York | Republican | 1896–1962 |
| Ralph Izard | 1789–1795 | 3 | South Carolina | Federalist | 1741/1742–1804 |
| Andrew Jackson | 1797–1798 1823–1825 | 1, 2 | Tennessee | Democratic-Republican | 1767–1845 |
| Henry M. Jackson | 1953–1983 | 1 | Washington | Democratic | 1912–1983 |
| Howell Edmunds Jackson | 1881–1886 | 1 | Tennessee | Democratic | 1832–1895 |
| James Jackson | 1793–1795 1801–1806 | 2, 3 | Georgia | Democratic-Republican | 1757–1806 |
| Samuel D. Jackson | 1944 | 3 | Indiana | Democratic | 1895–1951 |
| William Purnell Jackson | 1912–1914 | 1 | Maryland | Republican | 1868–1939 |
| Charles Tillinghast James | 1851–1857 | 1 | Rhode Island | Democratic | 1805–1862 |
| Ollie Murray James | 1913–1918 | 2 | Kentucky | Democratic | 1871–1918 |
| Spencer Jarnagin | 1843–1847 | 2 | Tennessee | Whig | 1792–1853 |
| Thomas Jordan Jarvis | 1894–1895 | 3 | North Carolina | Democratic | 1836–1915 |
| Jacob Javits | 1957–1981 | 3 | New York | Republican | 1904–1986 |
| Jim Jeffords | 1989–2001 2001–2007 | 1 | Vermont | Republican Independent | 1934–2014 |
| William E. Jenner | 1944–1945 1947–1959 | 1, 3 | Indiana | Republican | 1908–1985 |
| Benning W. Jenness | 1845–1846 | 2 | New Hampshire | Democratic | 1806–1879 |
| Roger Jepsen | 1979–1985 | 2 | Iowa | Republican | 1928–2020 |
| Daniel T. Jewett | 1870–1871 | 3 | Missouri | Republican | 1807–1906 |
| Mike Johanns | 2009–2015 | 2 | Nebraska | Republican | 1950–present |
| Andrew Johnson | 1857–1862 1875 | 1 | Tennessee | Democratic | 1808–1875 |
| Charles Fletcher Johnson | 1911–1917 | 1 | Maine | Democratic | 1859–1930 |
| Edwin C. Johnson | 1937–1955 | 2 | Colorado | Democratic | 1884–1970 |
| Edwin S. Johnson | 1915–1921 | 3 | South Dakota | Democratic | 1857–1933 |
| Henry Johnson | 1818–1823 1823–1824 1844–1849 | 2, 3 | Louisiana | Democratic-Republican National Republican Whig | 1783–1864 |
| Herschel V. Johnson | 1848–1849 | 2 | Georgia | Democratic | 1812–1880 |
| Hiram Johnson | 1917–1945 | 1 | California | Republican | 1866–1945 |
| Lyndon B. Johnson | 1949–1961 | 2 | Texas | Democratic | 1908–1973 |
| Magnus Johnson | 1923–1925 | 2 | Minnesota | Farmer–Labor | 1871–1936 |
| Martin N. Johnson | 1909 | 3 | North Dakota | Republican | 1850–1909 |
| Reverdy Johnson | 1845–1849 1863–1868 | 1 | Maryland | Whig Democratic | 1796–1876 |
| Richard Mentor Johnson | 1819–1824 1824–1829 | 2 | Kentucky | Democratic-Republican Democratic | 1780–1850 |
| Robert Ward Johnson | 1853–1861 | 3 | Arkansas | Democratic | 1814–1879 |
| Tim Johnson | 1997–2015 | 2 | South Dakota | Democratic | 1946–2024 |
| Waldo P. Johnson | 1861–1862 | 2 | Missouri | Democratic | 1817–1885 |
| William Samuel Johnson | 1789–1791 | 3 | Connecticut | Federalist | 1727–1819 |
| J. Bennett Johnston | 1972–1997 | 2 | Louisiana | Democratic | 1932–present |
| John W. Johnston | 1870–1871 1871–1883 | 2 | Virginia | Democratic | 1818–1889 |
| Joseph F. Johnston | 1907–1913 | 3 | Alabama | Democratic | 1843–1913 |
| Josiah S. Johnston | 1824–1833 | 3 | Louisiana | National Republican | 1784–1833 |
| Olin D. Johnston | 1945–1965 | 3 | South Carolina | Democratic | 1896–1965 |
| Rienzi Melville Johnston | 1913 | 2 | Texas | Democratic | 1849–1926 |
| Samuel Johnston | 1789–1793 | 3 | North Carolina | Federalist | 1733–1816 |
| Benjamin F. Jonas | 1879–1885 | 3 | Louisiana | Democratic | 1834–1911 |
| Andrieus A. Jones | 1917–1927 | 1 | New Mexico | Democratic | 1862–1927 |
| Charles W. Jones | 1875–1887 | 1 | Florida | Democratic | 1834–1897 |
| Doug Jones | 2018–2021 | 2 | Alabama | Democratic | 1954–present |
| George Jones | 1807 | 2 | Georgia | Democratic-Republican | 1766–1838 |
| George Wallace Jones | 1848–1859 | 2 | Iowa | Democratic | 1804–1896 |
| James C. Jones | 1851–1856 1856–1857 | 1 | Tennessee | Whig Democratic | 1809–1859 |
| James Kimbrough Jones | 1885–1903 | 3 | Arkansas | Democratic | 1839–1908 |
| John Percival Jones | 1873–1895 1895–1901 1901–1903 | 3 | Nevada | Republican Silverite Republican | 1829–1912 |
| Wesley Livsey Jones | 1909–1932 | 3 | Washington | Republican | 1863–1932 |
| B. Everett Jordan | 1958–1973 | 2 | North Carolina | Democratic | 1896–1974 |
| Leonard B. Jordan | 1962–1973 | 2 | Idaho | Republican | 1899–1983 |
| Elias Kane | 1825–1835 | 3 | Illinois | Democratic | 1794–1835 |
| David Karnes | 1987–1989 | 1 | Nebraska | Republican | 1948–2020 |
| Nancy Kassebaum | 1978–1997 | 2 | Kansas | Republican | 1932–present |
| Bob Kasten | 1981–1993 | 3 | Wisconsin | Republican | 1942–present |
| Ted Kaufman | 2009–2010 | 2 | Delaware | Democratic | 1939–present |
| William Marmaduke Kavanaugh | 1913 | 2 | Arkansas | Democratic | 1866–1915 |
| Hamilton Fish Kean | 1929–1935 | 1 | New Jersey | Republican | 1862–1941 |
| John Kean | 1899–1911 | 1 | New Jersey | Republican | 1852–1914 |
| Thomas Kearns | 1901–1905 | 1 | Utah | Republican | 1862–1918 |
| Kenneth Keating | 1959–1965 | 1 | New York | Republican | 1900–1975 |
| Estes Kefauver | 1949–1963 | 2 | Tennessee | Democratic | 1903–1963 |
| Frank B. Kellogg | 1917–1923 | 1 | Minnesota | Republican | 1856–1937 |
| William Pitt Kellogg | 1868–1872 1877–1883 | 2, 3 | Louisiana | Republican | 1830–1918 |
| James K. Kelly | 1871–1877 | 2 | Oregon | Democratic | 1819–1903 |
| William Kelly | 1822–1825 | 3 | Alabama | Democratic-Republican | 1786–1834 |
| James P. Kem | 1947–1953 | 1 | Missouri | Republican | 1890–1965 |
| Dirk Kempthorne | 1993–1999 | 3 | Idaho | Republican | 1951–present |
| John B. Kendrick | 1917–1933 | 1 | Wyoming | Democratic | 1857–1933 |
| John E. Kenna | 1883–1893 | 2 | West Virginia | Democratic | 1848–1893 |
| Anthony Kennedy | 1857–1863 | 1 | Maryland | American | 1810–1892 |
| John F. Kennedy | 1953–1960 | 1 | Massachusetts | Democratic | 1917–1963 |
| Robert F. Kennedy | 1965–1968 | 1 | New York | Democratic | 1925–1968 |
| Ted Kennedy | 1962–2009 | 1 | Massachusetts | Democratic | 1932–2009 |
| Richard R. Kenney | 1897–1901 | 2 | Delaware | Democratic | 1856–1931 |
| Joseph Kent | 1833–1837 | 1 | Maryland | Whig | 1779–1837 |
| William S. Kenyon | 1911–1922 | 2 | Iowa | Republican | 1869–1933 |
| John W. Kern | 1911–1917 | 1 | Indiana | Democratic | 1849–1917 |
| Francis Kernan | 1875–1881 | 1 | New York | Democratic | 1816–1892 |
| John Leeds Kerr | 1841–1843 | 3 | Maryland | Whig | 1780–1844 |
| Joseph Kerr | 1814–1815 | 1 | Ohio | Democratic-Republican | 1765–1837 |
| Robert S. Kerr | 1949–1963 | 2 | Oklahoma | Democratic | 1896–1963 |
| Bob Kerrey | 1989–2001 | 1 | Nebraska | Democratic | 1943–present |
| John Kerry | 1985–2013 | 2 | Massachusetts | Democratic | 1943–present |
| David M. Key | 1875–1877 | 1 | Tennessee | Democratic | 1824–1900 |
| Henry W. Keyes | 1919–1937 | 2 | New Hampshire | Republican | 1862–1938 |
| Harley M. Kilgore | 1941–1956 | 1 | West Virginia | Democratic | 1893–1956 |
| John Pendleton King | 1833–1837 | 2 | Georgia | Democratic | 1799–1888 |
| Preston King | 1857–1863 | 1 | New York | Republican | 1806–1865 |
| Rufus King | 1789–1796 1813–1825 | 3 | New York | Federalist | 1755–1827 |
| William H. King | 1917–1941 | 1 | Utah | Democratic | 1863–1949 |
| William R. King | 1819–1844 1848–1852 | 2, 3 | Alabama | Democratic | 1786–1853 |
| William F. Kirby | 1916–1921 | 3 | Arkansas | Democratic | 1867–1934 |
| Mark Kirk | 2010–2017 | 3 | Illinois | Republican | 1959–present |
| Paul G. Kirk | 2009–2010 | 1 | Massachusetts | Democratic | 1938–present |
| Samuel J. Kirkwood | 1866–1867 1877–1881 | 2, 3 | Iowa | Republican | 1813–1894 |
| Aaron Kitchell | 1805–1809 | 2 | New Jersey | Democratic-Republican | 1744–1820 |
| Alfred B. Kittredge | 1901–1909 | 3 | South Dakota | Republican | 1861–1911 |
| Nehemiah R. Knight | 1821–1824 1824–1832 1832–1841 | 2 | Rhode Island | Democratic-Republican National Republican Whig | 1780–1854 |
| William Knowland | 1945–1959 | 1 | California | Republican | 1908–1974 |
| Philander C. Knox | 1904–1909 1917–1921 | 1 | Pennsylvania | Republican | 1853–1921 |
| Herb Kohl | 1989–2013 | 1 | Wisconsin | Democratic | 1935–2023 |
| Bob Krueger | 1993 | 1 | Texas | Democratic | 1935–2022 |
| Thomas Kuchel | 1953–1969 | 3 | California | Republican | 1910–1994 |
| Jon Kyl | 1995–2013 2018 | 1 3 | Arizona | Republican | 1942–present |
| James H. Kyle | 1891–1901 | 3 | South Dakota | Populist | 1854–1901 |
| Robert M. La Follette | 1906–1925 | 1 | Wisconsin | Republican | 1855–1925 |
| Robert M. La Follette Jr. | 1925–1934 1934–1947 | 1 | Wisconsin | Republican Progressive | 1895–1953 |
| Abner Lacock | 1813–1819 | 3 | Pennsylvania | Democratic-Republican | 1770–1837 |
| Edwin F. Ladd | 1921–1925 | 3 | North Dakota | Republican | 1859–1925 |
| William Laird III | 1956 | 1 | West Virginia | Democratic | 1916–1974 |
| Lucius Quintus Cincinnatus Lamar | 1877–1885 | 2 | Mississippi | Democratic | 1825–1893 |
| John Lambert | 1809–1815 | 1 | New Jersey | Democratic-Republican | 1746–1823 |
| Mary Landrieu | 1997–2015 | 2 | Louisiana | Democratic | 1955–present |
| Harry Lane | 1913–1917 | 2 | Oregon | Democratic | 1855–1917 |
| Henry S. Lane | 1861–1867 | 3 | Indiana | Republican | 1811–1881 |
| Jim Lane | 1861–1866 | 2 | Kansas | Republican | 1814–1866 |
| Joseph Lane | 1859–1861 | 3 | Oregon | Democratic | 1801–1881 |
| John Langdon | 1789–1793 1793–1801 | 3 | New Hampshire | Federalist Democratic-Republican | 1741–1819 |
| William Langer | 1941–1959 | 1 | North Dakota | Republican | 1886–1959 |
| James Lanman | 1819–1825 | 3 | Connecticut | Democratic-Republican | 1767–1841 |
| Elbridge G. Lapham | 1881–1885 | 3 | New York | Republican | 1814–1890 |
| Octaviano Ambrosio Larrazolo | 1928–1929 | 1 | New Mexico | Republican | 1859–1930 |
| Milton Latham | 1860–1863 | 1 | California | Democratic | 1827–1882 |
| Asbury Latimer | 1903–1908 | 3 | South Carolina | Democratic | 1851–1908 |
| Henry Latimer | 1795–1801 | 1 | Delaware | Federalist | 1752–1819 |
| John Laurance | 1796–1800 | 3 | New York | Federalist | 1750–1810 |
| Frank Lausche | 1957–1969 | 3 | Ohio | Democratic | 1895–1990 |
| Frank Lautenberg | 1982–2001 2003–2013 | 1, 2 | New Jersey | Democratic | 1924–2013 |
| Paul Laxalt | 1974–1987 | 3 | Nevada | Republican | 1922–2018 |
| Luke Lea | 1911–1917 | 1 | Tennessee | Democratic | 1879–1945 |
| Edward L. Leahy | 1949–1950 | 1 | Rhode Island | Democratic | 1886–1953 |
| Patrick Leahy | 1975–2023 | 3 | Vermont | Democratic | 1940–present |
| Walter Leake | 1817–1820 | 1 | Mississippi | Democratic-Republican | 1762–1825 |
| Blair Lee I | 1914–1917 | 1 | Maryland | Democratic | 1857–1944 |
| Joshua B. Lee | 1937–1943 | 2 | Oklahoma | Democratic | 1892–1967 |
| Richard Henry Lee | 1789–1792 | 2 | Virginia | Democratic-Republican | 1732–1794 |
| Herbert H. Lehman | 1950–1957 | 3 | New York | Democratic | 1878–1963 |
| Michael Leib | 1809–1814 | 1 | Pennsylvania | Democratic-Republican | 1760–1822 |
| Benjamin W. Leigh | 1834–1836 | 2 | Virginia | National Republican | 1781–1849 |
| George LeMieux | 2009–2011 | 3 | Florida | Republican | 1969–present |
| Alton Lennon | 1953–1954 | 2 | North Carolina | Democratic | 1906–1986 |
| Irvine Lenroot | 1918–1927 | 3 | Wisconsin | Republican | 1869–1949 |
| Carl Levin | 1979–2015 | 2 | Michigan | Democratic | 1934–2021 |
| Dixon Hall Lewis | 1844–1848 | 2 | Alabama | Democratic | 1802–1848 |
| J. Hamilton Lewis | 1913–1919 1931–1939 | 2 | Illinois | Democratic | 1863–1939 |
| John F. Lewis | 1870–1875 | 1 | Virginia | Republican | 1818–1895 |
| Joe Lieberman | 1989–2006 2006–2013 | 1 | Connecticut | Democratic Independent Democrat | 1942–2024 |
| Blanche Lincoln | 1999–2011 | 3 | Arkansas | Democratic | 1960–present |
| William Lindsay | 1893–1901 | 2 | Kentucky | Democratic | 1835–1909 |
| Lewis F. Linn | 1833–1843 | 3 | Missouri | Democratic | 1796–1843 |
| Henry F. Lippitt | 1911–1917 | 1 | Rhode Island | Republican | 1856–1933 |
| Samuel Livermore | 1793–1801 | 2 | New Hampshire | Federalist | 1732–1803 |
| Edward Livingston | 1829–1831 | 2 | Louisiana | Democratic | 1764–1836 |
| Edward Lloyd | 1819–1824 1824–1826 | 3 | Maryland | Democratic-Republican Democratic | 1779–1834 |
| James Lloyd | 1797–1800 | 3 | Maryland | Federalist | 1745–1820 |
| James Lloyd | 1808–1813 1822–1824 1824–1826 | 1, 2 | Massachusetts | Federalist National Republican National Republican | 1769–1831 |
| Cyrus Locher | 1928 | 3 | Ohio | Democratic | 1878–1929 |
| Francis Locke Jr. | 1814–1815 | 3 | North Carolina | Democratic-Republican | 1776–1823 |
| Henry Cabot Lodge | 1893–1924 | 1 | Massachusetts | Republican | 1850–1924 |
| Henry Cabot Lodge Jr. | 1937–1944 1947–1953 | 1, 2 | Massachusetts | Republican | 1902–1985 |
| Kelly Loeffler | 2020–2021 | 3 | Georgia | Republican | 1970–present |
| Scott Loftin | 1936 | 1 | Florida | Democratic | 1878–1953 |
| George Logan | 1801–1807 | 3 | Pennsylvania | Democratic-Republican | 1753–1821 |
| John A. Logan | 1871–1877 1879–1886 | 2, 3 | Illinois | Republican | 1826–1886 |
| M. M. Logan | 1931–1939 | 2 | Kentucky | Democratic | 1874–1939 |
| William Logan | 1819–1820 | 3 | Kentucky | Democratic-Republican | 1776–1822 |
| Augustine Lonergan | 1933–1939 | 3 | Connecticut | Democratic | 1874–1947 |
| Chester I. Long | 1903–1909 | 3 | Kansas | Republican | 1860–1934 |
| Edward V. Long | 1960–1968 | 3 | Missouri | Democratic | 1908–1972 |
| Huey Long | 1932–1935 | 2 | Louisiana | Democratic | 1893–1935 |
| Oren E. Long | 1959–1963 | 3 | Hawaii | Democratic | 1889–1965 |
| Rose McConnell Long | 1936–1937 | 2 | Louisiana | Democratic | 1892–1970 |
| Russell B. Long | 1948–1987 | 3 | Louisiana | Democratic | 1918–2003 |
| William Lorimer | 1909–1912 | 3 | Illinois | Republican | 1861–1934 |
| Trent Lott | 1989–2007 | 1 | Mississippi | Republican | 1941–present |
| Walter Lowrie | 1819–1825 | 3 | Pennsylvania | Democratic-Republican | 1784–1868 |
| Scott W. Lucas | 1939–1951 | 3 | Illinois | Democratic | 1892–1968 |
| Richard Lugar | 1977–2013 | 1 | Indiana | Republican | 1932–2019 |
| Alva M. Lumpkin | 1941 | 2 | South Carolina | Democratic | 1886–1941 |
| Wilson Lumpkin | 1837–1841 | 2 | Georgia | Democratic | 1783–1870 |
| Ernest Lundeen | 1937–1940 | 2 | Minnesota | Farmer–Labor | 1878–1940 |
| Hall S. Lusk | 1960 | 2 | Oregon | Democratic | 1883–1983 |
| Lucius Lyon | 1837–1839 | 1 | Michigan | Democratic | 1800–1851 |
| Willis Benson Machen | 1872–1873 | 3 | Kentucky | Democratic | 1810–1893 |
| Connie Mack III | 1989–2001 | 1 | Florida | Republican | 1940–present |
| Samuel Maclay | 1803–1809 | 1 | Pennsylvania | Democratic-Republican | 1741–1811 |
| William Maclay | 1789–1791 | 1 | Pennsylvania | Democratic-Republican | 1737–1804 |
| Nathaniel Macon | 1815–1824 1824–1828 | 3 | North Carolina | Democratic-Republican Democratic | 1757–1837 |
| Warren Magnuson | 1944–1981 | 3 | Washington | Democratic | 1905–1989 |
| Allan B. Magruder | 1812–1813 | 3 | Louisiana | Democratic-Republican | 1775–1822 |
| William Mahone | 1881–1887 | 1 | Virginia | Readjuster | 1826–1895 |
| Francis Malbone | 1809 | 1 | Rhode Island | Federalist | 1759–1809 |
| Stephen Mallory | 1851–1861 | 1 | Florida | Democratic | 1812–1873 |
| Stephen Mallory II | 1897–1907 | 3 | Florida | Democratic | 1848–1907 |
| George W. Malone | 1947–1959 | 1 | Nevada | Republican | 1890–1961 |
| Francis T. Maloney | 1935–1945 | 1 | Connecticut | Democratic | 1894–1945 |
| Joe Manchin | 2010–2025 | 1 | West Virginia | Democratic Independent | 1947–present |
| Charles F. Manderson | 1883–1895 | 2 | Nebraska | Republican | 1837–1911 |
| Willie Person Mangum | 1831–1833 1833–1836 1840–1853 | 2, 3 | North Carolina | Democratic National Republican Whig | 1792–1861 |
| Mike Mansfield | 1953–1977 | 1 | Montana | Democratic | 1903–2001 |
| Lee Mantle | 1895–1896 1896–1899 | 1 | Montana | Republican Silver Republican | 1851–1934 |
| William L. Marcy | 1831–1833 | 3 | New York | Democratic | 1786–1857 |
| William Marks | 1825–1831 | 3 | Pennsylvania | National Republican | 1778–1858 |
| Humphrey Marshall | 1795–1801 | 3 | Kentucky | Federalist | 1760–1841 |
| Gilman Marston | 1889 | 2 | New Hampshire | Republican | 1811–1890 |
| Alexander Martin | 1793–1799 | 2 | North Carolina | Democratic-Republican | 1740–1807 |
| Edward Martin | 1947–1959 | 1 | Pennsylvania | Republican | 1879–1967 |
| George B. Martin | 1918–1919 | 2 | Kentucky | Democratic | 1876–1945 |
| John Martin | 1893–1895 | 2 | Kansas | Democratic | 1833–1913 |
| Thomas E. Martin | 1955–1961 | 2 | Iowa | Republican | 1893–1971 |
| Thomas S. Martin | 1895–1919 | 2 | Virginia | Democratic | 1847–1919 |
| James Edgar Martine | 1911–1917 | 1 | New Jersey | Democratic | 1850–1925 |
| Mel Martínez | 2005–2009 | 3 | Florida | Republican | 1946–present |
| Armistead Thomson Mason | 1816–1817 | 2 | Virginia | Democratic-Republican | 1787–1819 |
| James Murray Mason | 1847–1861 | 1 | Virginia | Democratic | 1798–1871 |
| Jeremiah Mason | 1813–1817 | 3 | New Hampshire | Federalist | 1768–1848 |
| Jonathan Mason | 1800–1803 | 1 | Massachusetts | Federalist | 1756–1831 |
| Stevens Thomson Mason | 1794–1803 | 1 | Virginia | Democratic-Republican | 1760–1803 |
| William E. Mason | 1897–1903 | 3 | Illinois | Republican | 1850–1921 |
| William A. Massey | 1912–1913 | 1 | Nevada | Republican | 1856–1914 |
| Harlan Mathews | 1993–1994 | 2 | Tennessee | Democratic | 1927–2014 |
| Elisha Mathewson | 1807–1811 | 2 | Rhode Island | Democratic-Republican | 1767–1853 |
| Charles Mathias | 1969–1987 | 3 | Maryland | Republican | 1922–2010 |
| Spark Matsunaga | 1977–1990 | 1 | Hawaii | Democratic | 1916–1990 |
| Stanley Matthews | 1877–1879 | 3 | Ohio | Republican | 1824–1889 |
| Mack Mattingly | 1981–1987 | 3 | Georgia | Republican | 1931–present |
| Samuel B. Maxey | 1875–1887 | 1 | Texas | Democratic | 1825–1895 |
| Burnet R. Maybank | 1941–1954 | 2 | South Carolina | Democratic | 1899–1954 |
| Earle Bradford Mayfield | 1923–1929 | 1 | Texas | Democratic | 1881–1964 |
| William Gibbs McAdoo | 1933–1938 | 2 | California | Democratic | 1863–1941 |
| George W. McBride | 1895–1901 | 3 | Oregon | Republican | 1854–1911 |
| John McCain | 1987–2018 | 3 | Arizona | Republican | 1936–2018 |
| Pat McCarran | 1933–1954 | 3 | Nevada | Democratic | 1876–1954 |
| Eugene McCarthy | 1959–1971 | 1 | Minnesota | Democratic | 1916–2005 |
| Joseph McCarthy | 1947–1957 | 1 | Wisconsin | Republican | 1908–1957 |
| Claire McCaskill | 2007–2019 | 1 | Missouri | Democratic | 1953–present |
| John L. McClellan | 1943–1977 | 2 | Arkansas | Democratic | 1896–1977 |
| Jim McClure | 1973–1991 | 2 | Idaho | Republican | 1924–2011 |
| Louis E. McComas | 1899–1905 | 1 | Maryland | Republican | 1846–1907 |
| William J. McConnell | 1890–1891 | 3 | Idaho | Republican | 1839–1925 |
| Medill McCormick | 1919–1925 | 2 | Illinois | Republican | 1877–1925 |
| James B. McCreary | 1903–1909 | 3 | Kentucky | Democratic | 1838–1918 |
| Thomas C. McCreery | 1868–1871 1873–1879 | 2, 3 | Kentucky | Democratic | 1816–1890 |
| Roscoe C. McCulloch | 1929–1930 | 3 | Ohio | Republican | 1880–1958 |
| Porter J. McCumber | 1899–1923 | 1 | North Dakota | Republican | 1858–1933 |
| James W. McDill | 1881–1883 | 2 | Iowa | Republican | 1834–1894 |
| Alexander McDonald | 1868–1871 | 2 | Arkansas | Republican | 1832–1903 |
| Joseph E. McDonald | 1875–1881 | 1 | Indiana | Democratic | 1819–1891 |
| James A. McDougall | 1861–1867 | 3 | California | Democratic | 1817–1867 |
| George McDuffie | 1842–1846 | 3 | South Carolina | Democratic | 1790–1851 |
| Samuel D. McEnery | 1897–1910 | 3 | Louisiana | Democratic | 1837–1910 |
| Ernest McFarland | 1941–1953 | 1 | Arizona | Democratic | 1894–1984 |
| Gale W. McGee | 1959–1977 | 1 | Wyoming | Democratic | 1915–1992 |
| George McGill | 1930–1939 | 3 | Kansas | Democratic | 1879–1963 |
| George McGovern | 1963–1981 | 3 | South Dakota | Democratic | 1922–2012 |
| J. Howard McGrath | 1947–1949 | 1 | Rhode Island | Democratic | 1903–1966 |
| Joseph McIlvaine | 1823–1824 1824–1826 | 1 | New Jersey | Democratic-Republican National Republican | 1769–1826 |
| Thomas J. McIntyre | 1962–1979 | 2 | New Hampshire | Democratic | 1915–1992 |
| Samuel McKean | 1833–1839 | 1 | Pennsylvania | Democratic | 1787–1841 |
| Kenneth McKellar | 1917–1953 | 1 | Tennessee | Democratic | 1869–1957 |
| John McKinley | 1826–1831 1837 | 3 | Alabama | Democratic | 1780–1852 |
| William B. McKinley | 1921–1926 | 3 | Illinois | Republican | 1856–1926 |
| Louis McLane | 1827–1829 | 1 | Delaware | Democratic | 1786–1857 |
| Anselm J. McLaurin | 1894–1895 1901–1909 | 2 | Mississippi | Democratic | 1848–1909 |
| John L. McLaurin | 1897–1903 | 3 | South Carolina | Democratic | 1860–1934 |
| George P. McLean | 1911–1929 | 1 | Connecticut | Republican | 1857–1932 |
| John McLean | 1824–1825 1829–1830 | 2, 3 | Illinois | Democratic | 1791–1830 |
| Brien McMahon | 1945–1952 | 3 | Connecticut | Democratic | 1903–1952 |
| William H. McMaster | 1925–1931 | 2 | South Dakota | Republican | 1877–1968 |
| James McMillan | 1889–1902 | 2 | Michigan | Republican | 1838–1902 |
| Samuel J. R. McMillan | 1875–1887 | 2 | Minnesota | Republican | 1826–1897 |
| Patrick V. McNamara | 1955–1966 | 2 | Michigan | Democratic | 1894–1966 |
| Charles L. McNary | 1917–1918 1918–1944 | 2 | Oregon | Republican | 1874–1944 |
| John R. McPherson | 1877–1895 | 2 | New Jersey | Democratic | 1833–1897 |
| John J. McRae | 1851–1852 | 1 | Mississippi | Democratic | 1815–1868 |
| Samuel McRoberts | 1841–1843 | 2 | Illinois | Democratic | 1799–1843 |
| Martha McSally | 2019–2020 | 3 | Arizona | Republican | 1966–present |
| James M. Mead | 1938–1947 | 1 | New York | Democratic | 1885–1964 |
| Rice W. Means | 1924–1927 | 3 | Colorado | Republican | 1877–1949 |
| Edwin L. Mechem | 1962–1964 | 1 | New Mexico | Republican | 1912–2002 |
| Return J. Meigs Jr. | 1808–1810 | 1 | Ohio | Democratic-Republican | 1764–1825 |
| John Melcher | 1977–1989 | 1 | Montana | Democratic | 1924–2018 |
| Prentiss Mellen | 1818–1820 | 1 | Massachusetts | Federalist | 1764–1840 |
| Bob Menendez | 2006–2024 | 1 | New Jersey | Democratic | 1954–present |
| David Meriwether | 1852 | 3 | Kentucky | Democratic | 1800–1893 |
| William Duhurst Merrick | 1838–1845 | 1 | Maryland | Whig | 1793–1857 |
| Augustus Summerfield Merrimon | 1873–1879 | 3 | North Carolina | Democratic | 1830–1892 |
| Jesse H. Metcalf | 1924–1937 | 2 | Rhode Island | Republican | 1860–1942 |
| Lee Metcalf | 1961–1978 | 2 | Montana | Democratic | 1911–1978 |
| Thomas Metcalfe | 1848–1849 | 3 | Kentucky | Whig | 1780–1855 |
| Howard Metzenbaum | 1974 1976–1995 | 1, 3 | Ohio | Democratic | 1917–2008 |
| Barbara Mikulski | 1987–2017 | 3 | Maryland | Democratic | 1936–present |
| Joseph Millard | 1901–1907 | 2 | Nebraska | Republican | 1836–1922 |
| John Milledge | 1806–1809 | 3 | Georgia | Democratic-Republican | 1757–1818 |
| Bert H. Miller | 1949 | 2 | Idaho | Democratic | 1879–1949 |
| Homer V. M. Miller | 1869–1871 | 2 | Georgia | Democratic | 1814–1896 |
| Jack Miller | 1961–1973 | 2 | Iowa | Republican | 1916–1994 |
| Jacob W. Miller | 1841–1853 | 2 | New Jersey | Whig | 1800–1862 |
| John E. Miller | 1937–1941 | 2 | Arkansas | Democratic | 1888–1981 |
| John Franklin Miller | 1881–1886 | 1 | California | Republican | 1831–1886 |
| Stephen Decatur Miller | 1831–1833 | 3 | South Carolina | Nullifier | 1787–1838 |
| Warner Miller | 1881–1887 | 1 | New York | Republican | 1838–1918 |
| Zell Miller | 2000–2005 | 3 | Georgia | Democratic | 1932–2018 |
| Eugene Millikin | 1941–1957 | 3 | Colorado | Republican | 1891–1958 |
| Elijah H. Mills | 1820–1824 1824–1827 | 1 | Massachusetts | Federalist National Republican | 1776–1829 |
| Roger Q. Mills | 1892–1899 | 1 | Texas | Democratic | 1832–1911 |
| John Gerald Milton | 1938 | 1 | New Jersey | Democratic | 1881–1977 |
| William Hall Milton | 1908–1909 | 3 | Florida | Democratic | 1864–1942 |
| Sherman Minton | 1935–1941 | 1 | Indiana | Democratic | 1890–1965 |
| Charles B. Mitchel | 1861 | 3 | Arkansas | Democratic | 1815–1864 |
| George J. Mitchell | 1980–1995 | 1 | Maine | Democratic | 1933–present |
| Hugh Mitchell | 1945–1946 | 1 | Washington | Democratic | 1907–1996 |
| John H. Mitchell | 1873–1879 1885–1897 1901–1905 | 1 | Oregon | Republican | 1835–1905 |
| John I. Mitchell | 1881–1887 | 1 | Pennsylvania | Republican | 1838–1907 |
| John L. Mitchell | 1893–1899 | 3 | Wisconsin | Democratic | 1842–1904 |
| Stephen Mix Mitchell | 1793–1795 | 2, 3 | Connecticut | Federalist | 1743–1835 |
| Samuel L. Mitchill | 1804–1809 | 1 | New York | Democratic-Republican | 1764–1831 |
| Walter Mondale | 1964–1976 | 2 | Minnesota | Democratic | 1928–2021 |
| Hernando Money | 1897–1911 | 1 | Mississippi | Democratic | 1839–1912 |
| James Monroe | 1790–1794 | 1 | Virginia | Democratic-Republican | 1758–1831 |
| Mike Monroney | 1951–1969 | 3 | Oklahoma | Democratic | 1902–1980 |
| Joseph Montoya | 1964–1977 | 1 | New Mexico | Democratic | 1915–1978 |
| Blair Moody | 1951–1952 | 1 | Michigan | Democratic | 1902–1954 |
| Gideon C. Moody | 1889–1891 | 3 | South Dakota | Republican | 1832–1904 |
| Wyman B. S. Moor | 1848 | 1 | Maine | Democratic | 1811–1869 |
| A. Harry Moore | 1935–1938 | 1 | New Jersey | Democratic | 1879–1952 |
| Andrew Moore | 1804–1809 | 1, 2 | Virginia | Democratic-Republican | 1752–1821 |
| Edward H. Moore | 1943–1949 | 2 | Oklahoma | Republican | 1871–1950 |
| Gabriel Moore | 1831–1833 1833–1837 | 3 | Alabama | Democratic National Republican | 1785–1845 |
| James Turner Morehead | 1841–1847 | 2 | Kentucky | Whig | 1797–1854 |
| Edwin D. Morgan | 1863–1869 | 1 | New York | Republican | 1811–1883 |
| John Tyler Morgan | 1877–1907 | 2 | Alabama | Democratic | 1824–1907 |
| Robert Burren Morgan | 1975–1981 | 3 | North Carolina | Democratic | 1925–2016 |
| David L. Morril | 1817–1823 | 2 | New Hampshire | Democratic-Republican | 1772–1849 |
| Justin Smith Morrill | 1867–1898 | 3 | Vermont | Republican | 1810–1898 |
| Lot M. Morrill | 1861–1869 1869–1876 | 1, 2 | Maine | Republican | 1813–1883 |
| Gouverneur Morris | 1800–1803 | 1 | New York | Federalist | 1752–1816 |
| Robert Morris | 1789–1795 | 3 | Pennsylvania | Federalist | 1734–1806 |
| Thomas Morris | 1833–1839 | 1 | Ohio | Democratic | 1776–1844 |
| Cameron A. Morrison | 1930–1932 | 3 | North Carolina | Democratic | 1869–1953 |
| Dwight Morrow | 1930–1931 | 2 | New Jersey | Republican | 1873–1931 |
| Jeremiah Morrow | 1813–1819 | 3 | Ohio | Democratic-Republican | 1771–1852 |
| Wayne Morse | 1945–1952 1952–1955 1955–1969 | 3 | Oregon | Republican Independent Democratic | 1900–1974 |
| Jackson Morton | 1849–1855 | 3 | Florida | Whig | 1794–1874 |
| Oliver P. Morton | 1867–1877 | 3 | Indiana | Republican | 1823–1877 |
| Thruston Ballard Morton | 1957–1968 | 3 | Kentucky | Republican | 1907–1982 |
| Mike Braun | 2019–2025 | 1 | Indiana | Republican | 1954–present |
| Carol Moseley Braun | 1993–1999 | 3 | Illinois | Democratic | 1947–present |
| George H. Moses | 1918–1933 | 3 | New Hampshire | Republican | 1869–1944 |
| John Moses | 1945 | 3 | North Dakota | Democratic | 1885–1945 |
| Frank Moss | 1959–1977 | 1 | Utah | Democratic | 1911–2003 |
| Alexandre Mouton | 1837–1842 | 3 | Louisiana | Democratic | 1804–1885 |
| Daniel Patrick Moynihan | 1977–2001 | 1 | New York | Democratic | 1927–2003 |
| Peter Muhlenberg | 1801 | 3 | Pennsylvania | Democratic-Republican | 1746–1807 |
| Frederick W. Mulkey | 1907 1918 | 2 | Oregon | Republican | 1874–1924 |
| Karl Mundt | 1948–1973 | 2 | South Dakota | Republican | 1900–1974 |
| Orrice Abram Murdock Jr. | 1941–1947 | 1 | Utah | Democratic | 1893–1979 |
| Frank Murkowski | 1981–2002 | 3 | Alaska | Republican | 1933–present |
| Edward Murphy Jr. | 1893–1899 | 1 | New York | Democratic | 1834–1911 |
| George Murphy | 1965–1971 | 1 | California | Republican | 1902–1992 |
| Maurice J. Murphy Jr. | 1961–1962 | 2 | New Hampshire | Republican | 1927–2002 |
| Richard L. Murphy | 1933–1936 | 3 | Iowa | Democratic | 1875–1936 |
| James E. Murray | 1934–1961 | 2 | Montana | Democratic | 1876–1961 |
| Edmund Muskie | 1959–1980 | 1 | Maine | Democratic | 1914–1996 |
| Francis J. Myers | 1945–1951 | 3 | Pennsylvania | Democratic | 1901–1956 |
| Henry L. Myers | 1911–1923 | 1 | Montana | Democratic | 1862–1943 |
| Arnold Naudain | 1830–1836 | 1 | Delaware | National Republican | 1790–1872 |
| Matthew M. Neely | 1923–1929 1931–1941 1949–1958 | 1, 2 | West Virginia | Democratic | 1874–1958 |
| Arthur E. Nelson | 1942–1943 | 2 | Minnesota | Republican | 1892–1955 |
| Ben Nelson | 2001–2013 | 1 | Nebraska | Democratic | 1941–present |
| Bill Nelson | 2001–2019 | 1 | Florida | Democratic | 1942–present |
| Gaylord Nelson | 1963–1981 | 3 | Wisconsin | Democratic | 1916–2005 |
| Knute Nelson | 1895–1923 | 2 | Minnesota | Republican | 1843–1923 |
| James Nesmith | 1861–1867 | 3 | Oregon | Democratic | 1820–1885 |
| Maurine Neuberger | 1960–1967 | 2 | Oregon | Democratic | 1907–2000 |
| Richard L. Neuberger | 1955–1960 | 2 | Oregon | Democratic | 1912–1960 |
| Harry Stewart New | 1917–1923 | 1 | Indiana | Republican | 1858–1937 |
| Truman Handy Newberry | 1919–1922 | 2 | Michigan | Republican | 1864–1945 |
| Francis G. Newlands | 1903–1917 | 3 | Nevada | Democratic | 1846–1917 |
| Robert C. Nicholas | 1836–1841 | 2 | Louisiana | Democratic | 1787–1856 |
| Wilson Cary Nicholas | 1799–1804 | 2 | Virginia | Democratic-Republican | 1761–1820 |
| Alfred O. P. Nicholson | 1840–1842 1859–1861 | 1, 2 | Tennessee | Democratic | 1808–1876 |
| Samuel D. Nicholson | 1921–1923 | 2 | Colorado | Republican | 1859–1923 |
| Don Nickles | 1981–2005 | 3 | Oklahoma | Republican | 1948–present |
| John Milton Niles | 1835–1839 1843–1849 | 1, 3 | Connecticut | Democratic | 1787–1856 |
| George S. Nixon | 1905–1912 | 1 | Nevada | Republican | 1860–1912 |
| Richard Nixon | 1950–1953 | 3 | California | Republican | 1913–1994 |
| James Noble | 1816–1831 | 1 | Indiana | National Republican | 1785–1831 |
| Peter Norbeck | 1921–1936 | 3 | South Dakota | Republican | 1870–1936 |
| George W. Norris | 1913–1936 1936–1943 | 2 | Nebraska | Republican Independent | 1861–1944 |
| Moses Norris Jr. | 1849–1855 | 3 | New Hampshire | Democratic | 1799–1855 |
| William North | 1798 | 1 | New York | Federalist | 1755–1836 |
| Daniel Sheldon Norton | 1865–1870 | 2 | Minnesota | Republican | 1829–1870 |
| John Norvell | 1837–1841 | 2 | Michigan | Democratic | 1789–1850 |
| Thomas M. Norwood | 1871–1877 | 2 | Georgia | Democratic | 1830–1913 |
| Amos Nourse | 1857 | 1 | Maine | Republican | 1794–1877 |
| John F. Nugent | 1918–1921 | 3 | Idaho | Democratic | 1868–1931 |
| Sam Nunn | 1972–1997 | 2 | Georgia | Democratic | 1938–present |
| Gerald Nye | 1925–1945 | 3 | North Dakota | Republican | 1892–1971 |
| James W. Nye | 1864–1873 | 3 | Nevada | Republican | 1815–1876 |
| Herbert O'Conor | 1947–1953 | 1 | Maryland | Democratic | 1896–1960 |
| W. Lee O'Daniel | 1941–1949 | 2 | Texas | Democratic | 1890–1969 |
| James Aloysius O'Gorman | 1911–1917 | 1 | New York | Democratic | 1860–1943 |
| Joseph C. O'Mahoney | 1934–1953 1954–1961 | 1, 2 | Wyoming | Democratic | 1884–1962 |
| Barack Obama | 2005–2008 | 3 | Illinois | Democratic | 1961–present |
| Tasker Oddie | 1921–1933 | 3 | Nevada | Republican | 1870–1950 |
| Aaron Ogden | 1801–1803 | 1 | New Jersey | Federalist | 1756–1839 |
| Richard J. Oglesby | 1873–1879 | 3 | Illinois | Republican | 1824–1899 |
| Simeon Olcott | 1801–1805 | 2 | New Hampshire | Federalist | 1735–1815 |
| George T. Oliver | 1909–1917 | 1 | Pennsylvania | Republican | 1848–1919 |
| Thomas W. Osborn | 1868–1873 | 3 | Florida | Republican | 1833–1898 |
| Harrison Gray Otis | 1817–1822 | 2 | Massachusetts | Federalist | 1765–1848 |
| Lee Slater Overman | 1903–1930 | 3 | North Carolina | Democratic | 1854–1930 |
| John H. Overton | 1933–1948 | 3 | Louisiana | Democratic | 1875–1948 |
| Robert Latham Owen | 1907–1925 | 2 | Oklahoma | Democratic | 1856–1947 |
| Bob Packwood | 1969–1995 | 3 | Oregon | Republican | 1932–present |
| Algernon Paddock | 1875–1881 1887–1893 | 1 | Nebraska | Republican | 1830–1897 |
| Carroll S. Page | 1908–1923 | 1 | Vermont | Republican | 1843–1925 |
| John Page | 1836–1837 | 3 | New Hampshire | Democratic | 1787–1865 |
| Elijah Paine | 1795–1801 | 3 | Vermont | Federalist | 1757–1842 |
| John M. Palmer | 1891–1897 | 3 | Illinois | Democratic | 1817–1900 |
| Thomas W. Palmer | 1883–1889 | 2 | Michigan | Republican | 1830–1913 |
| William A. Palmer | 1818–1824 1824–1825 | 3 | Vermont | Democratic-Republican National Republican | 1781–1860 |
| Nahum Parker | 1807–1810 | 3 | New Hampshire | Democratic-Republican | 1760–1839 |
| Richard E. Parker | 1836–1837 | 2 | Virginia | Democratic | 1783–1840 |
| Albion Parris | 1827–1828 | 1 | Maine | Democratic | 1788–1857 |
| John Fabyan Parrott | 1819–1824 1824–1825 | 3 | New Hampshire | Democratic-Republican National Republican | 1767–1836 |
| Frank C. Partridge | 1930–1931 | 1 | Vermont | Republican | 1861–1943 |
| Samuel Pasco | 1887–1899 | 1 | Florida | Democratic | 1834–1917 |
| John Pastore | 1950–1976 | 1 | Rhode Island | Democratic | 1907–2000 |
| William Paterson | 1789–1790 | 2 | New Jersey | Federalist | 1745–1806 |
| David T. Patterson | 1866–1869 | 1 | Tennessee | Democratic | 1818–1891 |
| James W. Patterson | 1867–1873 | 3 | New Hampshire | Republican | 1823–1893 |
| John J. Patterson | 1873–1879 | 3 | South Carolina | Republican | 1830–1912 |
| Roscoe C. Patterson | 1929–1935 | 1 | Missouri | Republican | 1876–1954 |
| Thomas M. Patterson | 1901–1907 | 2 | Colorado | Democratic | 1839–1916 |
| John Patton Jr. | 1894–1895 | 1 | Michigan | Republican | 1850–1907 |
| Frederick G. Payne | 1953–1959 | 1 | Maine | Republican | 1904–1978 |
| Henry B. Payne | 1885–1891 | 3 | Ohio | Democratic | 1810–1896 |
| Thomas H. Paynter | 1907–1913 | 2 | Kentucky | Democratic | 1851–1921 |
| Roger C. Peace | 1941 | 2 | South Carolina | Democratic | 1899–1968 |
| James Pearce | 1843–1856 1856–1862 | 3 | Maryland | Whig Democratic | 1805–1862 |
| James B. Pearson | 1962–1978 | 2 | Kansas | Republican | 1920–2009 |
| Henry R. Pease | 1874–1875 | 1 | Mississippi | Republican | 1835–1907 |
| William A. Peffer | 1891–1897 | 3 | Kansas | Populist | 1831–1912 |
| Claiborne Pell | 1961–1997 | 2 | Rhode Island | Democratic | 1918–2009 |
| George H. Pendleton | 1879–1885 | 3 | Ohio | Democratic | 1825–1889 |
| Isaac S. Pennybacker | 1845–1847 | 1 | Virginia | Democratic | 1805–1847 |
| Boies Penrose | 1897–1921 | 3 | Pennsylvania | Republican | 1860–1921 |
| Claude Pepper | 1936–1951 | 3 | Florida | Democratic | 1900–1989 |
| George W. Pepper | 1922–1927 | 3 | Pennsylvania | Republican | 1867–1961 |
| Charles H. Percy | 1967–1985 | 2 | Illinois | Republican | 1919–2011 |
| LeRoy Percy | 1910–1913 | 2 | Mississippi | Democratic | 1860–1929 |
| David Perdue | 2015–2021 | 2 | Georgia | Republican | 1949–present |
| Bishop W. Perkins | 1892–1893 | 2 | Kansas | Republican | 1841–1894 |
| George Clement Perkins | 1893–1915 | 3 | California | Republican | 1839–1923 |
| Kirtland I. Perky | 1912–1913 | 3 | Idaho | Democratic | 1867–1939 |
| Richard F. Pettigrew | 1889–1896 1896–1901 | 2 | South Dakota | Republican Silver Republican | 1848–1926 |
| John Pettit | 1853–1855 | 3 | Indiana | Democratic | 1807–1877 |
| Edmund Pettus | 1897–1907 | 3 | Alabama | Democratic | 1821–1907 |
| James D. Phelan | 1915–1921 | 3 | California | Democratic | 1861–1930 |
| Samuel S. Phelps | 1839–1851 1853–1854 | 1, 3 | Vermont | Whig | 1793–1855 |
| Lawrence C. Phipps | 1919–1931 | 2 | Colorado | Republican | 1862–1958 |
| Israel Pickens | 1826 | 3 | Alabama | Democratic | 1780–1827 |
| Timothy Pickering | 1803–1811 | 2 | Massachusetts | Federalist | 1745–1829 |
| Franklin Pierce | 1837–1842 | 3 | New Hampshire | Democratic | 1804–1869 |
| Gilbert A. Pierce | 1889–1891 | 3 | North Dakota | Republican | 1839–1901 |
| Austin F. Pike | 1883–1886 | 2 | New Hampshire | Republican | 1819–1886 |
| Samuel H. Piles | 1905–1911 | 1 | Washington | Republican | 1858–1940 |
| Charles Pinckney | 1798–1801 | 2 | South Carolina | Democratic-Republican | 1754–1824 |
| William B. Pine | 1925–1931 | 2 | Oklahoma | Republican | 1877–1942 |
| William Pinkney | 1819–1822 | 1 | Maryland | Democratic-Republican | 1764–1822 |
| Key Pittman | 1913–1940 | 1 | Nevada | Democratic | 1872–1940 |
| Orville H. Platt | 1879–1905 | 3 | Connecticut | Republican | 1827–1905 |
| Thomas C. Platt | 1881 1897–1909 | 1, 3 | New York | Republican | 1833–1910 |
| James Pleasants | 1819–1822 | 2 | Virginia | Democratic-Republican | 1769–1836 |
| Preston B. Plumb | 1877–1891 | 2 | Kansas | Republican | 1837–1891 |
| William Plumer | 1802–1807 | 3 | New Hampshire | Federalist | 1759–1850 |
| George Poindexter | 1830–1831 1831–1835 | 2 | Mississippi | Democratic National Republican | 1779–1853 |
| Miles Poindexter | 1911–1913 1913–1915 1915–1923 | 1 | Washington | Republican Progressive Republican | 1868–1946 |
| Luke P. Poland | 1865–1867 | 3 | Vermont | Republican | 1815–1887 |
| Trusten Polk | 1857–1862 | 1 | Missouri | Democratic | 1811–1876 |
| William P. Pollock | 1918–1919 | 2 | South Carolina | Democratic | 1870–1922 |
| Atlee Pomerene | 1911–1923 | 1 | Ohio | Democratic | 1863–1937 |
| Samuel C. Pomeroy | 1861–1873 | 3 | Kansas | Republican | 1816–1891 |
| John Pool | 1868–1873 | 3 | North Carolina | Republican | 1826–1884 |
| James P. Pope | 1933–1939 | 3 | Idaho | Democratic | 1884–1966 |
| John Pope | 1807–1813 | 3 | Kentucky | Democratic-Republican | 1770–1845 |
| Alexander Porter | 1833–1836 1836–1837 1843–1844 | 3 | Louisiana | National Republican Whig Whig | 1785–1844 |
| Augustus Seymour Porter | 1840–1845 | 1 | Michigan | Whig | 1798–1872 |
| Rob Portman | 2011–2023 | 3 | Ohio | Republican | 1955–present |
| Thomas Posey | 1812–1813 | 2 | Louisiana | Democratic-Republican | 1750–1818 |
| Charles E. Potter | 1952–1959 | 1 | Michigan | Republican | 1916–1979 |
| Samuel J. Potter | 1803–1804 | 1 | Rhode Island | Democratic-Republican | 1753–1804 |
| Richard Potts | 1793–1796 | 1 | Maryland | Federalist | 1753–1808 |
| Lazarus W. Powell | 1859–1865 | 2 | Kentucky | Democratic | 1812–1867 |
| Thomas C. Power | 1890–1895 | 2 | Montana | Republican | 1839–1923 |
| Daniel D. Pratt | 1869–1875 | 1 | Indiana | Republican | 1813–1877 |
| Thomas Pratt | 1850–1856 1856–1857 | 1 | Maryland | Whig Democratic | 1804–1869 |
| Samuel Prentiss | 1831–1836 1836–1842 | 3 | Vermont | National Republican Whig | 1782–1857 |
| Larry Pressler | 1979–1997 | 2 | South Dakota | Republican | 1942–present |
| William C. Preston | 1833–1837 1837–1842 | 3 | South Carolina | Nullifier Whig | 1794–1860 |
| Samuel Price | 1876–1877 | 1 | West Virginia | Democratic | 1805–1884 |
| Oliver H. Prince | 1828–1829 | 2 | Georgia | Democratic | 1787–1837 |
| Jeter Connelly Pritchard | 1895–1903 | 3 | North Carolina | Republican | 1857–1921 |
| Redfield Proctor | 1891–1908 | 1 | Vermont | Republican | 1831–1908 |
| Winston L. Prouty | 1959–1971 | 1 | Vermont | Republican | 1906–1971 |
| William Proxmire | 1957–1989 | 1 | Wisconsin | Democratic | 1915–2005 |
| David Pryor | 1979–1997 | 2 | Arkansas | Democratic | 1934–2024 |
| Luke Pryor | 1880 | 3 | Alabama | Democratic | 1820–1900 |
| Mark Pryor | 2003–2015 | 2 | Arkansas | Democratic | 1963–present |
| George E. Pugh | 1855–1861 | 3 | Ohio | Democratic | 1822–1876 |
| James L. Pugh | 1880–1897 | 3 | Alabama | Democratic | 1820–1907 |
| William E. Purcell | 1910–1911 | 3 | North Dakota | Democratic | 1856–1928 |
| William A. Purtell | 1952 1953–1959 | 1, 3 | Connecticut | Republican | 1897–1978 |
| Gladys Pyle | 1938–1939 | 3 | South Dakota | Republican | 1890–1989 |
| Joseph V. Quarles | 1899–1905 | 1 | Wisconsin | Republican | 1843–1911 |
| Matthew Quay | 1887–1899 1901–1904 | 1 | Pennsylvania | Republican | 1833–1904 |
| Dan Quayle | 1981–1989 | 3 | Indiana | Republican | 1947–present |
| George L. P. Radcliffe | 1935–1947 | 1 | Maryland | Democratic | 1877–1974 |
| Samuel M. Ralston | 1923–1925 | 1 | Indiana | Democratic | 1857–1925 |
| Alexander Ramsey | 1863–1875 | 1 | Minnesota | Republican | 1815–1903 |
| Jennings Randolph | 1958–1985 | 2 | West Virginia | Democratic | 1902–1998 |
| John Randolph of Roanoke | 1825–1827 | 1 | Virginia | Democratic | 1773–1833 |
| Theodore Fitz Randolph | 1875–1881 | 1 | New Jersey | Democratic | 1826–1883 |
| Joseph E. Ransdell | 1913–1931 | 2 | Louisiana | Democratic | 1858–1954 |
| Matt Whitaker Ransom | 1872–1895 | 2 | North Carolina | Democratic | 1826–1904 |
| Robert Rantoul Jr. | 1851 | 1 | Massachusetts | Democratic | 1805–1852 |
| Joseph Lafayette Rawlins | 1897–1903 | 1 | Utah | Democratic | 1850–1926 |
| Charles A. Rawson | 1922 | 2 | Iowa | Republican | 1867–1936 |
| Isidor Rayner | 1905–1912 | 1 | Maryland | Democratic | 1850–1912 |
| George Read | 1789–1793 | 1 | Delaware | Federalist | 1733–1798 |
| Jacob Read | 1795–1801 | 3 | South Carolina | Federalist | 1752–1816 |
| John Henninger Reagan | 1887–1891 | 3 | Texas | Democratic | 1818–1905 |
| Alfred E. Reames | 1938 | 3 | Oregon | Democratic | 1870–1943 |
| Clyde M. Reed | 1939–1949 | 3 | Kansas | Republican | 1871–1949 |
| David A. Reed | 1922–1935 | 1 | Pennsylvania | Republican | 1880–1953 |
| James A. Reed | 1911–1929 | 1 | Missouri | Democratic | 1861–1944 |
| Philip Reed | 1806–1813 | 3 | Maryland | Democratic-Republican | 1760–1829 |
| Thomas Buck Reed | 1826–1827 1829 | 1, 2 | Mississippi | Democratic | 1787–1829 |
| David Settle Reid | 1854–1859 | 2 | North Carolina | Democratic | 1813–1891 |
| Harry Reid | 1987–2017 | 3 | Nevada | Democratic | 1939–2021 |
| Hiram Rhodes Revels | 1870–1871 | 2 | Mississippi | Republican | 1827–1901 |
| Chapman Revercomb | 1943–1949 1956–1959 | 1, 2 | West Virginia | Republican | 1895–1979 |
| Robert Rice Reynolds | 1932–1945 | 3 | North Carolina | Democratic | 1884–1963 |
| Samuel W. Reynolds | 1954 | 1 | Nebraska | Republican | 1890–1988 |
| Robert Barnwell Rhett | 1850–1852 | 2 | South Carolina | Democratic | 1800–1876 |
| Abraham Ribicoff | 1963–1981 | 3 | Connecticut | Democratic | 1910–1998 |
| Benjamin F. Rice | 1868–1872 1872–1873 | 3 | Arkansas | Republican Liberal Republican | 1828–1905 |
| Henry Mower Rice | 1858–1863 | 1 | Minnesota | Democratic | 1816–1894 |
| Harry A. Richardson | 1907–1913 | 2 | Delaware | Republican | 1853–1928 |
| William Alexander Richardson | 1863–1865 | 2 | Illinois | Democratic | 1811–1875 |
| George R. Riddle | 1864–1867 | 1 | Delaware | Democratic | 1817–1867 |
| Harrison H. Riddleberger | 1883–1889 | 2 | Virginia | Readjuster | 1844–1890 |
| Henry M. Ridgely | 1827–1829 | 2 | Delaware | Democratic | 1779–1847 |
| Donald Riegle | 1977–1995 | 1 | Michigan | Democratic | 1938–present |
| William Cabell Rives | 1832–1834 1836–1839 1841–1845 | 1, 2 | Virginia | Democratic Democratic Whig | 1793–1868 |
| William N. Roach | 1893–1899 | 1 | North Dakota | Democratic | 1840–1902 |
| William H. Roane | 1837–1841 | 2 | Virginia | Democratic | 1787–1845 |
| Chuck Robb | 1989–2001 | 1 | Virginia | Democratic | 1939–present |
| Asher Robbins | 1825–1836 1836–1839 | 1 | Rhode Island | National Republican Whig | 1761–1845 |
| Jonathan Roberts | 1814–1821 | 1 | Pennsylvania | Democratic-Republican | 1771–1854 |
| Pat Roberts | 1997–2021 | 2 | Kansas | Republican | 1936–present |
| Absalom Willis Robertson | 1946–1966 | 2 | Virginia | Democratic | 1887–1971 |
| Edward V. Robertson | 1943–1949 | 2 | Wyoming | Republican | 1881–1963 |
| Thomas J. Robertson | 1868–1877 | 2 | South Carolina | Republican | 1823–1897 |
| Arthur Raymond Robinson | 1925–1935 | 1 | Indiana | Republican | 1881–1961 |
| John McCracken Robinson | 1830–1841 | 2 | Illinois | Democratic | 1794–1843 |
| Jonathan Robinson | 1807–1815 | 1 | Vermont | Democratic-Republican | 1756–1819 |
| Joseph Taylor Robinson | 1913–1937 | 2 | Arkansas | Democratic | 1872–1937 |
| Moses Robinson | 1791–1797 | 1 | Vermont | Democratic-Republican | 1741–1813 |
| John M. Robsion | 1930 | 2 | Kentucky | Republican | 1873–1948 |
| Jay Rockefeller | 1985–2015 | 2 | West Virginia | Democratic | 1937–present |
| Julius Rockwell | 1854–1855 | 2 | Massachusetts | Whig | 1805–1888 |
| Caesar Augustus Rodney | 1822–1823 | 1 | Delaware | Democratic-Republican | 1772–1824 |
| Daniel Rodney | 1826–1827 | 2 | Delaware | National Republican | 1764–1846 |
| Edward H. Rollins | 1877–1883 | 2 | New Hampshire | Republican | 1824–1889 |
| Mitt Romney | 2019–2025 | 1 | Utah | Republican | 1947–present |
| Elihu Root | 1909–1915 | 3 | New York | Republican | 1845–1937 |
| Joseph Rosier | 1941–1942 | 2 | West Virginia | Democratic | 1870–1951 |
| Edmund G. Ross | 1866–1871 | 2 | Kansas | Republican | 1826–1907 |
| James Ross | 1794–1803 | 1 | Pennsylvania | Federalist | 1762–1847 |
| Jonathan Ross | 1899–1900 | 3 | Vermont | Republican | 1826–1905 |
| William Roth | 1971–2001 | 1 | Delaware | Republican | 1921–2003 |
| John Rowan | 1825–1831 | 3 | Kentucky | Democratic | 1773–1843 |
| Marco Rubio | 2011–2025 | 3 | Florida | Republican | 1971–present |
| Warren Rudman | 1981–1993 | 3 | New Hampshire | Republican | 1930–2012 |
| Benjamin Ruggles | 1815–1824 1824–1833 | 1 | Ohio | Democratic-Republican National Republican | 1783–1857 |
| John Ruggles | 1835–1841 | 2 | Maine | Democratic | 1789–1874 |
| Thomas Jefferson Rusk | 1846–1857 | 1 | Texas | Democratic | 1803–1857 |
| Donald S. Russell | 1965–1966 | 3 | South Carolina | Democratic | 1906–1998 |
| Richard Russell Jr. | 1933–1971 | 2 | Georgia | Democratic | 1897–1971 |
| John Rutherfurd | 1791–1798 | 1 | New Jersey | Federalist | 1760–1840 |
| Dwight M. Sabin | 1883–1889 | 2 | Minnesota | Republican | 1843–1902 |
| Frederic M. Sackett | 1925–1930 | 2 | Kentucky | Republican | 1868–1941 |
| Ken Salazar | 2005–2009 | 3 | Colorado | Democratic | 1955–present |
| Pierre Salinger | 1964 | 1 | California | Democratic | 1925–2004 |
| Leverett Saltonstall | 1945–1967 | 2 | Massachusetts | Republican | 1892–1979 |
| Newell Sanders | 1912–1913 | 2 | Tennessee | Republican | 1850–1939 |
| Wilbur F. Sanders | 1890–1893 | 1 | Montana | Republican | 1834–1905 |
| Nathan Sanford | 1815–1821 1826–1831 | 1 | New York | Democratic-Republican National Republican | 1777–1838 |
| Terry Sanford | 1986–1993 | 3 | North Carolina | Democratic | 1917–1998 |
| Rick Santorum | 1995–2007 | 1 | Pennsylvania | Republican | 1958–present |
| Paul Sarbanes | 1977–2007 | 1 | Maryland | Democratic | 1933–2020 |
| Aaron A. Sargent | 1873–1879 | 3 | California | Republican | 1827–1887 |
| Ben Sasse | 2015–2023 | 2 | Nebraska | Republican | 1972–present |
| Jim Sasser | 1977–1995 | 1 | Tennessee | Democratic | 1936–2024 |
| Eli Saulsbury | 1871–1889 | 2 | Delaware | Democratic | 1817–1893 |
| Willard Saulsbury Jr. | 1913–1919 | 2 | Delaware | Democratic | 1861–1927 |
| Willard Saulsbury Sr. | 1859–1871 | 2 | Delaware | Democratic | 1820–1892 |
| Alvin Saunders | 1877–1883 | 2 | Nebraska | Republican | 1817–1899 |
| Frederick A. Sawyer | 1868–1873 | 3 | South Carolina | Republican | 1822–1891 |
| Philetus Sawyer | 1881–1893 | 1 | Wisconsin | Republican | 1816–1900 |
| William B. Saxbe | 1969–1974 | 3 | Ohio | Republican | 1916–2010 |
| Thomas D. Schall | 1925–1935 | 2 | Minnesota | Republican | 1878–1935 |
| Harrison Schmitt | 1977–1983 | 1 | New Mexico | Republican | 1935–present |
| Andrew Frank Schoeppel | 1949–1962 | 2 | Kansas | Republican | 1894–1962 |
| James Schureman | 1799–1801 | 1 | New Jersey | Federalist | 1756–1824 |
| Carl Schurz | 1869–1871 1871–1875 | 1 | Missouri | Republican Liberal Republican | 1829–1906 |
| Karl C. Schuyler | 1932–1933 | 3 | Colorado | Republican | 1877–1933 |
| Philip Schuyler | 1789–1791 1797–1798 | 1 | New York | Federalist | 1733–1804 |
| Harry Schwartz | 1937–1943 | 2 | Wyoming | Democratic | 1869–1955 |
| Richard Schweiker | 1969–1981 | 3 | Pennsylvania | Republican | 1926–2015 |
| Lewis B. Schwellenbach | 1935–1940 | 1 | Washington | Democratic | 1894–1948 |
| Hugh Scott | 1959–1977 | 1 | Pennsylvania | Republican | 1900–1994 |
| John Scott | 1869–1875 | 1 | Pennsylvania | Republican | 1824–1896 |
| Nathan B. Scott | 1899–1911 | 1 | West Virginia | Republican | 1842–1924 |
| W. Kerr Scott | 1954–1958 | 2 | North Carolina | Democratic | 1896–1958 |
| William L. Scott | 1973–1979 | 2 | Virginia | Republican | 1915–1997 |
| James G. Scrugham | 1942–1945 | 1 | Nevada | Democratic | 1880–1945 |
| Fred A. Seaton | 1951–1952 | 2 | Nebraska | Republican | 1909–1974 |
| William K. Sebastian | 1848–1861 | 2 | Arkansas | Democratic | 1812–1865 |
| Theodore Sedgwick | 1796–1799 | 3 | Massachusetts | Federalist | 1746–1813 |
| James Semple | 1843–1847 | 2 | Illinois | Democratic | 1798–1866 |
| Jeff Sessions | 1997–2017 | 2 | Alabama | Republican | 1946–present |
| Ambrose Hundley Sevier | 1836–1848 | 3 | Arkansas | Democratic | 1801–1848 |
| William H. Seward | 1849–1855 1855–1861 | 3 | New York | Whig Republican | 1801–1872 |
| William Joyce Sewell | 1881–1887 1895–1901 | 1, 2 | New Jersey | Republican | 1835–1901 |
| Horatio Seymour | 1821–1824 1824–1833 | 1 | Vermont | Democratic-Republican National Republican | 1778–1857 |
| John Seymour | 1991–1992 | 1 | California | Republican | 1937–present |
| John F. Shafroth | 1913–1919 | 2 | Colorado | Democratic | 1854–1922 |
| William Sharon | 1875–1881 | 1 | Nevada | Republican | 1821–1885 |
| James Sheafe | 1801–1802 | 3 | New Hampshire | Federalist | 1755–1829 |
| William Paine Sheffield Sr. | 1884–1885 | 2 | Rhode Island | Republican | 1820–1907 |
| Richard Shelby | 1987–1994 1994–2023 | 3 | Alabama | Democratic Republican | 1934–present |
| Ether Shepley | 1833–1836 | 1 | Maine | Democratic | 1789–1877 |
| Morris Sheppard | 1913–1941 | 2 | Texas | Democratic | 1875–1941 |
| John Sherman | 1861–1877 1881–1897 | 1, 3 | Ohio | Republican | 1823–1900 |
| Lawrence Yates Sherman | 1913–1921 | 3 | Illinois | Republican | 1858–1939 |
| Roger Sherman | 1791–1793 | 3 | Connecticut | Federalist | 1721–1793 |
| James Shields | 1849–1855 1858–1859 1879 | 2, 3 | Illinois Minnesota Missouri | Democratic | 1810–1879 |
| John K. Shields | 1913–1925 | 2 | Tennessee | Democratic | 1858–1934 |
| Henrik Shipstead | 1923–1941 1941–1947 | 1 | Minnesota | Farmer–Labor Republican | 1881–1960 |
| Benjamin F. Shively | 1909–1916 | 3 | Indiana | Democratic | 1857–1916 |
| Samuel M. Shortridge | 1921–1933 | 3 | California | Republican | 1861–1952 |
| Hugh Ike Shott | 1942–1943 | 2 | West Virginia | Republican | 1866–1953 |
| George L. Shoup | 1890–1901 | 2 | Idaho | Republican | 1836–1904 |
| Nathaniel Silsbee | 1826–1835 | 2 | Massachusetts | National Republican | 1773–1850 |
| Furnifold McLendel Simmons | 1901–1931 | 1 | North Carolina | Democratic | 1854–1940 |
| James F. Simmons | 1841–1847 1857–1862 | 1, 2 | Rhode Island | Whig Republican | 1795–1864 |
| Joseph Simon | 1898–1903 | 3 | Oregon | Republican | 1851–1935 |
| Paul Simon | 1985–1997 | 2 | Illinois | Democratic | 1928–2003 |
| Alan Simpson | 1979–1997 | 2 | Wyoming | Republican | 1931–2025 |
| Milward Simpson | 1962–1967 | 2 | Wyoming | Republican | 1897–1993 |
| Kyrsten Sinema | 2019–2025 | 1 | Arizona | Democratic Independent | 1976–present |
| James H. Slater | 1879–1885 | 3 | Oregon | Democratic | 1826–1899 |
| James M. Slattery | 1939–1940 | 2 | Illinois | Democratic | 1878–1948 |
| John Slidell | 1853–1861 | 3 | Louisiana | Democratic | 1793–1871 |
| George Smathers | 1951–1969 | 3 | Florida | Democratic | 1913–2007 |
| William H. Smathers | 1937–1943 | 2 | New Jersey | Democratic | 1891–1955 |
| Benjamin A. Smith II | 1960–1962 | 1 | Massachusetts | Democratic | 1916–1991 |
| Bob Smith | 1990–2003 | 2 | New Hampshire | Republican | 1941–present |
| Daniel Smith | 1798 1805–1809 | 1, 2 | Tennessee | Democratic-Republican | 1748–1818 |
| Delazon Smith | 1859 | 2 | Oregon | Democratic | 1816–1860 |
| Ellison D. Smith | 1909–1944 | 3 | South Carolina | Democratic | 1864–1944 |
| Frank L. Smith | 1926–1928 | 3 | Illinois | Republican | 1867–1950 |
| Gordon H. Smith | 1997–2009 | 2 | Oregon | Republican | 1952–present |
| Howard Alexander Smith | 1944–1959 | 1 | New Jersey | Republican | 1880–1966 |
| Israel Smith | 1803–1807 | 1 | Vermont | Democratic-Republican | 1759–1810 |
| James Smith Jr. | 1893–1899 | 1 | New Jersey | Democratic | 1851–1927 |
| John Smith | 1803–1808 | 1 | Ohio | Democratic-Republican | 1735–1824 |
| John Smith | 1804–1813 | 3 | New York | Democratic-Republican | 1735–1816 |
| John Walter Smith | 1908–1921 | 3 | Maryland | Democratic | 1845–1925 |
| M. Hoke Smith | 1911–1921 | 3 | Georgia | Democratic | 1855–1931 |
| Marcus A. Smith | 1912–1921 | 3 | Arizona | Democratic | 1851–1924 |
| Margaret Chase Smith | 1949–1973 | 2 | Maine | Republican | 1897–1995 |
| Nathan Smith | 1833–1835 | 1 | Connecticut | National Republican | 1777–1835 |
| Oliver H. Smith | 1837–1843 | 3 | Indiana | Whig | 1794–1859 |
| Perry Smith | 1837–1843 | 3 | Connecticut | Democratic | 1783–1852 |
| Ralph T. Smith | 1969–1970 | 3 | Illinois | Republican | 1915–1972 |
| Samuel Smith | 1803–1815 1822–1824 1824–1833 | 1 | Maryland | Democratic-Republican Democratic-Republican Democratic | 1752–1839 |
| Truman Smith | 1849–1854 | 3 | Connecticut | Whig | 1791–1884 |
| William Smith | 1816–1823 1826–1831 | 2, 3 | South Carolina | Democratic-Republican Democratic | 1762–1840 |
| William Alden Smith | 1907–1919 | 2 | Michigan | Republican | 1859–1932 |
| Willis Smith | 1950–1953 | 2 | North Carolina | Democratic | 1887–1953 |
| Reed Smoot | 1903–1933 | 3 | Utah | Republican | 1862–1941 |
| Olympia Snowe | 1995–2013 | 1 | Maine | Republican | 1947–present |
| Pierre Soulé | 1847 1849–1853 | 2, 3 | Louisiana | Democratic | 1801–1870 |
| Samuel L. Southard | 1821–1823 1833–1837 1837–1842 | 1 | New Jersey | Democratic-Republican National Republican Whig | 1787–1842 |
| John Sparkman | 1946–1979 | 2 | Alabama | Democratic | 1899–1985 |
| Arlen Specter | 1981–2009 2009–2011 | 3 | Pennsylvania | Republican Democratic | 1930–2012 |
| Jesse Speight | 1845–1847 | 1 | Mississippi | Democratic | 1795–1847 |
| John S. Spence | 1836–1840 | 3 | Maryland | Whig | 1788–1840 |
| George E. Spencer | 1868–1879 | 3 | Alabama | Republican | 1836–1893 |
| Lloyd Spencer | 1941–1943 | 2 | Arkansas | Democratic | 1893–1981 |
| Selden P. Spencer | 1918–1925 | 3 | Missouri | Republican | 1862–1925 |
| William Spong Jr. | 1966–1973 | 2 | Virginia | Democratic | 1920–1997 |
| John Coit Spooner | 1885–1891 1897–1907 | 3 | Wisconsin | Republican | 1843–1919 |
| Peleg Sprague | 1829–1835 | 2 | Maine | National Republican | 1793–1880 |
| William Sprague III | 1842–1844 | 1 | Rhode Island | Whig | 1799–1856 |
| William Sprague IV | 1863–1873 1873–1875 | 1 | Rhode Island | Republican Liberal Republican | 1830–1915 |
| Presley Spruance | 1847–1853 | 2 | Delaware | Whig | 1785–1863 |
| Watson C. Squire | 1889–1897 | 3 | Washington | Republican | 1838–1926 |
| Debbie Stabenow | 2001–2025 | 1 | Michigan | Democratic | 1950–present |
| Robert Stafford | 1971–1989 | 1 | Vermont | Republican | 1913–2006 |
| Robert N. Stanfield | 1921–1927 | 3 | Oregon | Republican | 1877–1945 |
| William A. Stanfill | 1945–1946 | 2 | Kentucky | Republican | 1892–1971 |
| Leland Stanford | 1885–1893 | 3 | California | Republican | 1824–1893 |
| Augustus Owsley Stanley | 1919–1925 | 2 | Kentucky | Democratic | 1867–1958 |
| Joseph Stanton Jr. | 1790–1793 | 2 | Rhode Island | Democratic-Republican | 1739–1807 |
| Benjamin Stark | 1861–1862 | 2 | Oregon | Democratic | 1820–1898 |
| Ozora P. Stearns | 1871 | 2 | Minnesota | Republican | 1831–1896 |
| Daniel F. Steck | 1926–1931 | 2 | Iowa | Democratic | 1881–1950 |
| Frederick Steiwer | 1927–1938 | 3 | Oregon | Republican | 1883–1939 |
| John C. Stennis | 1947–1989 | 1 | Mississippi | Democratic | 1901–1995 |
| Hubert D. Stephens | 1923–1935 | 3 | Mississippi | Democratic | 1875–1946 |
| Isaac Stephenson | 1907–1915 | 2 | Wisconsin | Republican | 1829–1918 |
| Thomas Sterling | 1913–1925 | 3 | South Dakota | Republican | 1851–1930 |
| Ted Stevens | 1968–2009 | 2 | Alaska | Republican | 1923–2010 |
| Adlai Stevenson III | 1970–1981 | 3 | Illinois | Democratic | 1930–2021 |
| John W. Stevenson | 1871–1877 | 2 | Kentucky | Democratic | 1812–1886 |
| David Stewart | 1849–1850 | 3 | Maryland | Whig | 1800–1858 |
| David W. Stewart | 1926–1927 | 3 | Iowa | Republican | 1887–1974 |
| Donald Stewart | 1978–1981 | 3 | Alabama | Democratic | 1940–present |
| John Wolcott Stewart | 1908 | 2 | Vermont | Republican | 1825–1915 |
| Tom Stewart | 1938–1949 | 2 | Tennessee | Democratic | 1892–1972 |
| William Morris Stewart | 1864–1875 1887–1893 1893–1901 1901–1905 | 1 | Nevada | Republican Republican Silver Republican Republican | 1827–1909 |
| Francis B. Stockbridge | 1887–1894 | 1 | Michigan | Republican | 1826–1894 |
| John P. Stockton | 1865–1866 1869–1875 | 1, 2 | New Jersey | Democratic | 1826–1900 |
| Richard Stockton | 1796–1799 | 2 | New Jersey | Federalist | 1764–1828 |
| Robert F. Stockton | 1851–1853 | 1 | New Jersey | Democratic | 1795–1866 |
| Montfort Stokes | 1816–1823 | 2 | North Carolina | Democratic-Republican | 1762–1842 |
| David Stone | 1801–1807 1813–1814 | 3 | North Carolina | Democratic-Republican | 1770–1818 |
| Richard Stone | 1975–1980 | 3 | Florida | Democratic | 1928–2019 |
| William J. Stone | 1903–1918 | 3 | Missouri | Democratic | 1848–1918 |
| Clement Storer | 1817–1819 | 3 | New Hampshire | Democratic-Republican | 1760–1830 |
| Thomas M. Storke | 1938–1939 | 3 | California | Democratic | 1876–1971 |
| Luther Strange | 2017–2018 | 2 | Alabama | Republican | 1953–present |
| Robert Strange | 1836–1840 | 3 | North Carolina | Democratic | 1796–1854 |
| Caleb Strong | 1789–1796 | 2 | Massachusetts | Federalist | 1745–1819 |
| Charles E. Stuart | 1853–1859 | 2 | Michigan | Democratic | 1810–1887 |
| Daniel Sturgeon | 1840–1851 | 1 | Pennsylvania | Democratic | 1789–1878 |
| Patrick Joseph Sullivan | 1929–1930 | 1 | Wyoming | Republican | 1865–1935 |
| William V. Sullivan | 1898–1901 | 1 | Mississippi | Democratic | 1857–1918 |
| Charles Sumner | 1851–1857 1857–1872 1872–1874 | 1 | Massachusetts | Free Soil Republican Liberal Republican | 1811–1874 |
| Thomas Sumter | 1801–1810 | 2 | South Carolina | Democratic-Republican | 1734–1832 |
| John E. Sununu | 2003–2009 | 2 | New Hampshire | Republican | 1964–present |
| George Sutherland | 1905–1917 | 1 | Utah | Republican | 1862–1942 |
| Howard Sutherland | 1917–1923 | 1 | West Virginia | Republican | 1865–1950 |
| Claude A. Swanson | 1910–1933 | 1 | Virginia | Democratic | 1862–1939 |
| Benjamin Swift | 1833–1836 1836–1839 | 1 | Vermont | National Republican Whig | 1781–1847 |
| George R. Swift | 1946 | 2 | Alabama | Democratic | 1887–1972 |
| Stuart Symington | 1953–1976 | 1 | Missouri | Democratic | 1901–1988 |
| Steve Symms | 1981–1993 | 3 | Idaho | Republican | 1938–2024 |
| Horace Tabor | 1883 | 2 | Colorado | Republican | 1830–1899 |
| Kingsley A. Taft | 1946–1947 | 1 | Ohio | Republican | 1903–1970 |
| Robert A. Taft | 1939–1953 | 3 | Ohio | Republican | 1889–1953 |
| Robert Taft Jr. | 1971–1976 | 1 | Ohio | Republican | 1917–1993 |
| Thomas Taggart | 1916 | 3 | Indiana | Democratic | 1856–1929 |
| Charles Tait | 1809–1819 | 3 | Georgia | Democratic-Republican | 1768–1835 |
| Isham Talbot | 1815–1819 1820–1824 1824–1825 | 3 | Kentucky | Democratic-Republican Democratic-Republican National Republican | 1773–1837 |
| Jim Talent | 2002–2007 | 1 | Missouri | Republican | 1956–present |
| James Taliaferro | 1899–1911 | 1 | Florida | Democratic | 1847–1934 |
| Nathaniel P. Tallmadge | 1833–1839 1839–1844 | 1 | New York | Democratic Whig | 1795–1864 |
| Herman Talmadge | 1957–1981 | 3 | Georgia | Democratic | 1913–2002 |
| Benjamin Tappan | 1839–1845 | 1 | Ohio | Democratic | 1773–1857 |
| Josiah Tattnall | 1796–1799 | 2 | Georgia | Democratic-Republican | 1762–1803 |
| Glen H. Taylor | 1945–1951 | 3 | Idaho | Democratic | 1904–1984 |
| John Taylor | 1810–1816 | 2 | South Carolina | Democratic-Republican | 1770–1832 |
| John Taylor of Caroline | 1792–1794 1803 1822–1824 | 1, 2 | Virginia | Democratic-Republican | 1753–1824 |
| Robert Love Taylor | 1907–1912 | 2 | Tennessee | Democratic | 1850–1912 |
| Waller Taylor | 1816–1824 1824–1825 | 3 | Indiana | Democratic-Republican National Republican | 1786–1826 |
| Henry Tazewell | 1794–1799 | 2 | Virginia | Democratic-Republican | 1753–1799 |
| Littleton Waller Tazewell | 1824–1832 | 2 | Virginia | Democratic | 1774–1860 |
| Henry M. Teller | 1876–1882 1885–1897 1897–1901 1901–1909 | 2, 3 | Colorado | Republican Republican Silver Republican Democratic | 1830–1914 |
| John C. Ten Eyck | 1859–1865 | 2 | New Jersey | Republican | 1814–1879 |
| Joseph M. Terrell | 1910–1911 | 3 | Georgia | Democratic | 1861–1912 |
| Jon Tester | 2007–2025 | 1 | Montana | Democratic | 1956–present |
| John Milton Thayer | 1867–1871 | 2 | Nebraska | Republican | 1820–1906 |
| Charles S. Thomas | 1913–1921 | 3 | Colorado | Democratic | 1849–1934 |
| Craig L. Thomas | 1995–2007 | 1 | Wyoming | Republican | 1933–2007 |
| Elbert D. Thomas | 1933–1951 | 3 | Utah | Democratic | 1883–1953 |
| Elmer Thomas | 1927–1951 | 3 | Oklahoma | Democratic | 1876–1965 |
| Jesse B. Thomas | 1818–1824 1824–1829 | 3 | Illinois | Democratic-Republican National Republican | 1777–1853 |
| John Thomas | 1928–1933 1940–1945 | 2, 3 | Idaho | Republican | 1874–1945 |
| Fountain L. Thompson | 1909–1910 | 3 | North Dakota | Democratic | 1854–1942 |
| Fred Thompson | 1994–2003 | 2 | Tennessee | Republican | 1942–2015 |
| John Burton Thompson | 1853–1857 1857–1859 | 2 | Kentucky | Whig American | 1810–1874 |
| Thomas W. Thompson | 1814–1817 | 2 | New Hampshire | Federalist | 1766–1821 |
| William Henry Thompson | 1933–1934 | 1 | Nebraska | Democratic | 1853–1937 |
| William Howard Thompson | 1913–1919 | 2 | Kansas | Democratic | 1871–1928 |
| John Renshaw Thomson | 1853–1862 | 1 | New Jersey | Democratic | 1800–1862 |
| John Thornton | 1910–1915 | 3 | Louisiana | Democratic | 1846–1917 |
| Buckner Thruston | 1805–1809 | 2 | Kentucky | Democratic-Republican | 1763–1845 |
| Allen G. Thurman | 1869–1881 | 1 | Ohio | Democratic | 1813–1895 |
| Strom Thurmond | 1954–1956 1956–1964 1964–2003 | 2 | South Carolina | Democratic Democratic Republican | 1902–2003 |
| John Mellen Thurston | 1895–1901 | 2 | Nebraska | Republican | 1847–1916 |
| Edward John Thye | 1947–1959 | 1 | Minnesota | Republican | 1896–1969 |
| Isaac Tichenor | 1796–1797 1815–1821 | 1 | Vermont | Federalist | 1754–1848 |
| Edward Tiffin | 1807–1809 | 3 | Ohio | Democratic-Republican | 1766–1829 |
| Benjamin Tillman | 1895–1918 | 2 | South Carolina | Democratic | 1847–1918 |
| John Tipton | 1832–1839 | 1 | Indiana | Democratic | 1786–1839 |
| Thomas Tipton | 1867–1873 1873–1875 | 1 | Nebraska | Republican Liberal Republican | 1817–1899 |
| Charles W. Tobey | 1939–1953 | 3 | New Hampshire | Republican | 1880–1953 |
| Gideon Tomlinson | 1831–1837 | 3 | Connecticut | National Republican | 1780–1854 |
| Robert Toombs | 1853–1855 1855–1861 | 2 | Georgia | Whig Democratic | 1810–1885 |
| Pat Toomey | 2011–2023 | 3 | Pennsylvania | Republican | 1961–present |
| Robert Torricelli | 1997–2003 | 2 | New Jersey | Democratic | 1951–present |
| Isaac Toucey | 1852–1857 | 1 | Connecticut | Democratic | 1792–1869 |
| John Tower | 1961–1985 | 2 | Texas | Republican | 1925–1991 |
| Charles A. Towne | 1900–1901 | 1 | Minnesota | Democratic | 1858–1928 |
| Charles E. Townsend | 1911–1923 | 1 | Michigan | Republican | 1856–1924 |
| John G. Townsend Jr. | 1929–1941 | 1 | Delaware | Republican | 1871–1964 |
| Uriah Tracy | 1796–1807 | 3 | Connecticut | Federalist | 1755–1807 |
| Park Trammell | 1917–1936 | 1 | Florida | Democratic | 1876–1936 |
| Paul Trible | 1983–1989 | 1 | Virginia | Republican | 1946–present |
| William A. Trimble | 1819–1821 | 3 | Ohio | Democratic-Republican | 1786–1821 |
| James F. Trotter | 1838 | 1 | Mississippi | Democratic | 1802–1866 |
| George Troup | 1816–1818 1829–1833 | 2 | Georgia | Democratic-Republican Democratic | 1780–1856 |
| Harry S. Truman | 1935–1945 | 1 | Missouri | Democratic | 1884–1972 |
| Jonathan Trumbull Jr. | 1795–1796 | 3 | Connecticut | Federalist | 1740–1809 |
| Lyman Trumbull | 1855–1857 1857–1872 1872–1873 | 3 | Illinois | Democratic Republican Liberal Republican | 1813–1896 |
| Paul Tsongas | 1979–1985 | 2 | Massachusetts | Democratic | 1941–1997 |
| James M. Tunnell | 1941–1947 | 1 | Delaware | Democratic | 1879–1957 |
| John V. Tunney | 1971–1977 | 1 | California | Democratic | 1934–2018 |
| Thomas B. Turley | 1897–1901 | 2 | Tennessee | Democratic | 1845–1910 |
| George Turner | 1897–1901 1901–1903 | 3 | Washington | Silver Republican Democratic | 1850–1932 |
| James Turner | 1805–1816 | 2 | North Carolina | Democratic-Republican | 1766–1824 |
| Hopkins L. Turney | 1845–1851 | 1 | Tennessee | Democratic | 1797–1857 |
| David Turpie | 1863 1887–1899 | 1 | Indiana | Democratic | 1828–1909 |
| Joseph Tydings | 1965–1971 | 1 | Maryland | Democratic | 1928–2018 |
| Millard Tydings | 1927–1951 | 3 | Maryland | Democratic | 1890–1961 |
| John Tyler | 1827–1833 1833–1836 | 1 | Virginia | Democratic National Republican | 1790–1862 |
| Lawrence Tyson | 1925–1929 | 2 | Tennessee | Democratic | 1861–1929 |
| Mark Udall | 2009–2015 | 2 | Colorado | Democratic | 1950–present |
| Tom Udall | 2009–2021 | 2 | New Mexico | Democratic | 1948–present |
| William B. Umstead | 1946–1948 | 2 | North Carolina | Democratic | 1895–1954 |
| Joseph R. Underwood | 1847–1853 | 2 | Kentucky | Whig | 1791–1876 |
| Oscar Underwood | 1915–1927 | 3 | Alabama | Democratic | 1862–1929 |
| Thomas R. Underwood | 1951–1952 | 2 | Kentucky | Democratic | 1898–1956 |
| William Upham | 1843–1853 | 3 | Vermont | Whig | 1792–1853 |
| Robert W. Upton | 1953–1954 | 3 | New Hampshire | Republican | 1884–1972 |
| Martin Van Buren | 1821–1824 1824–1828 | 1 | New York | Democratic-Republican Democratic | 1782–1862 |
| Nicholas Van Dyke | 1817–1824 1824–1826 | 2 | Delaware | Federalist National Republican | 1770–1826 |
| Frederick Van Nuys | 1933–1944 | 3 | Indiana | Democratic | 1874–1944 |
| Peter G. Van Winkle | 1863–1867 1867–1869 | 1 | West Virginia | Union Republican | 1808–1872 |
| Charles Van Wyck | 1881–1887 | 1 | Nebraska | Republican | 1824–1895 |
| JD Vance | 2023–2025 | 3 | Ohio | Republican | 1984–present |
| Zebulon Baird Vance | 1879–1894 | 3 | North Carolina | Democratic | 1830–1894 |
| Arthur Vandenberg | 1928–1951 | 1 | Michigan | Republican | 1884–1951 |
| James K. Vardaman | 1913–1919 | 2 | Mississippi | Democratic | 1861–1930 |
| Joseph Bradley Varnum | 1811–1817 | 2 | Massachusetts | Democratic-Republican | 1751–1821 |
| Abraham B. Venable | 1803–1804 | 1 | Virginia | Democratic-Republican | 1758–1811 |
| George Graham Vest | 1879–1903 | 3 | Missouri | Democratic | 1830–1904 |
| George Vickers | 1868–1873 | 3 | Maryland | Democratic | 1801–1879 |
| William Freeman Vilas | 1891–1897 | 3 | Wisconsin | Democratic | 1840–1908 |
| John Vining | 1793–1798 | 2 | Delaware | Federalist | 1758–1802 |
| David Vitter | 2005–2017 | 3 | Louisiana | Republican | 1961–present |
| George Voinovich | 1999–2011 | 3 | Ohio | Republican | 1936–2016 |
| Daniel W. Voorhees | 1877–1897 | 3 | Indiana | Democratic | 1827–1897 |
| Benjamin Wade | 1851–1856 1856–1869 | 1 | Ohio | Whig Republican | 1800–1878 |
| Bainbridge Wadleigh | 1873–1879 | 3 | New Hampshire | Republican | 1831–1891 |
| James Wolcott Wadsworth Jr. | 1915–1927 | 3 | New York | Republican | 1877–1952 |
| George A. Waggaman | 1831–1835 | 2 | Louisiana | National Republican | 1782–1843 |
| Robert F. Wagner | 1927–1949 | 3 | New York | Democratic | 1877–1953 |
| Frederic C. Walcott | 1929–1935 | 1 | Connecticut | Republican | 1869–1949 |
| John Wales | 1849–1851 | 1 | Delaware | Whig | 1783–1863 |
| Freeman Walker | 1819–1821 | 2 | Georgia | Democratic-Republican | 1780–1827 |
| George Walker | 1814 | 2 | Kentucky | Democratic-Republican | 1763–1819 |
| Isaac P. Walker | 1848–1855 | 3 | Wisconsin | Democratic | 1815–1872 |
| James D. Walker | 1879–1885 | 3 | Arkansas | Democratic | 1830–1906 |
| John Walker | 1790 | 1 | Virginia | Federalist | 1744–1809 |
| John Williams Walker | 1819–1822 | 3 | Alabama | Democratic-Republican | 1783–1823 |
| Robert J. Walker | 1835–1845 | 2 | Mississippi | Democratic | 1801–1869 |
| Walter Walker | 1932 | 2 | Colorado | Democratic | 1883–1956 |
| Garret D. Wall | 1835–1841 | 2 | New Jersey | Democratic | 1783–1850 |
| James Walter Wall | 1863 | 1 | New Jersey | Democratic | 1820–1872 |
| William A. Wallace | 1875–1881 | 1 | Pennsylvania | Democratic | 1827–1896 |
| Monrad Wallgren | 1940–1945 | 1 | Washington | Democratic | 1891–1961 |
| Malcolm Wallop | 1977–1995 | 1 | Wyoming | Republican | 1933–2011 |
| Arthur Walsh | 1943–1944 | 1 | New Jersey | Democratic | 1896–1947 |
| David I. Walsh | 1919–1925 1926–1947 | 1, 2 | Massachusetts | Democratic | 1872–1947 |
| John Walsh | 2014–2015 | 2 | Montana | Democratic | 1960–present |
| Patrick Walsh | 1894–1895 | 2 | Georgia | Democratic | 1840–1899 |
| Thomas J. Walsh | 1913–1933 | 2 | Montana | Democratic | 1859–1933 |
| Herbert S. Walters | 1963–1964 | 2 | Tennessee | Democratic | 1891–1973 |
| Edward C. Walthall | 1885–1894 1895–1898 | 2 | Mississippi | Democratic | 1831–1898 |
| George Walton | 1795–1796 | 2 | Georgia | Federalist | 1749–1804 |
| Matthias Ward | 1858–1859 | 1 | Texas | Democratic | 1805–1861 |
| Nicholas Ware | 1821–1824 | 2 | Georgia | Democratic-Republican | 1769–1824 |
| John Warner | 1979–2009 | 2 | Virginia | Republican | 1927–2021 |
| Willard Warner | 1868–1871 | 2 | Alabama | Republican | 1826–1906 |
| William Warner | 1905–1911 | 1 | Missouri | Republican | 1840–1916 |
| Francis E. Warren | 1890–1893 1895–1929 | 1, 2 | Wyoming | Republican | 1844–1929 |
| William B. Washburn | 1874–1875 | 1 | Massachusetts | Republican | 1820–1887 |
| William D. Washburn | 1889–1895 | 2 | Minnesota | Republican | 1831–1912 |
| Charles W. Waterman | 1927–1932 | 3 | Colorado | Republican | 1861–1932 |
| Arthur Vivian Watkins | 1947–1959 | 1 | Utah | Republican | 1886–1973 |
| Clarence Wayland Watson | 1911–1913 | 2 | West Virginia | Democratic | 1864–1940 |
| James Watson | 1798–1800 | 1 | New York | Federalist | 1750–1806 |
| James Eli Watson | 1916–1933 | 3 | Indiana | Republican | 1864–1948 |
| Thomas E. Watson | 1921–1922 | 3 | Georgia | Democratic | 1856–1922 |
| Jim Webb | 2007–2013 | 1 | Virginia | Democratic | 1946–present |
| William R. Webb | 1913 | 2 | Tennessee | Democratic | 1842–1926 |
| Daniel Webster | 1827–1833 1833–1841 1845–1850 | 1 | Massachusetts | National Republican Whig Whig | 1782–1852 |
| John W. Weeks | 1913–1919 | 2 | Massachusetts | Republican | 1860–1926 |
| Sinclair Weeks | 1944 | 2 | Massachusetts | Republican | 1893–1972 |
| Lowell Weicker | 1971–1989 | 1 | Connecticut | Republican | 1931–2023 |
| Adonijah Welch | 1868–1869 | 1 | Florida | Republican | 1821–1889 |
| Herman Welker | 1951–1957 | 3 | Idaho | Republican | 1906–1957 |
| John B. Weller | 1852–1857 | 1 | California | Democratic | 1812–1875 |
| Ovington Weller | 1921–1927 | 3 | Maryland | Republican | 1862–1947 |
| George L. Wellington | 1897–1903 | 3 | Maryland | Democratic | 1852–1927 |
| John S. Wells | 1855 | 3 | New Hampshire | Democratic | 1803–1860 |
| William H. Wells | 1799–1804 1813–1817 | 2 | Delaware | Federalist | 1769–1829 |
| Paul Wellstone | 1991–2002 | 2 | Minnesota | Democratic | 1944–2002 |
| Joseph R. West | 1871–1872 1872 1872–1877 | 2 | Louisiana | Republican Liberal Republican Republican | 1822–1898 |
| William Stanley West | 1914 | 2 | Georgia | Democratic | 1849–1914 |
| James Westcott | 1845–1849 | 3 | Florida | Democratic | 1802–1880 |
| George P. Wetmore | 1895–1907 1908–1913 | 2 | Rhode Island | Republican | 1846–1921 |
| Jesse Wharton | 1814–1815 | 2 | Tennessee | Democratic-Republican | 1782–1833 |
| Burton K. Wheeler | 1923–1947 | 1 | Montana | Democratic | 1882–1975 |
| Kenneth S. Wherry | 1943–1951 | 2 | Nebraska | Republican | 1892–1951 |
| James Whitcomb | 1849–1852 | 3 | Indiana | Democratic | 1795–1852 |
| Albert Smith White | 1839–1845 | 1 | Indiana | Whig | 1803–1864 |
| Edward Douglass White | 1891–1894 | 3 | Louisiana | Democratic | 1845–1921 |
| Francis S. White | 1914–1915 | 3 | Alabama | Democratic | 1847–1922 |
| Hugh Lawson White | 1825–1835 1835–1836 1836–1840 | 2 | Tennessee | Democratic National Republican Whig | 1773–1840 |
| Samuel White | 1801–1809 | 1 | Delaware | Federalist | 1770–1809 |
| Stephen M. White | 1893–1899 | 1 | California | Democratic | 1853–1901 |
| Wallace H. White | 1931–1949 | 2 | Maine | Republican | 1877–1952 |
| Jenkin Whiteside | 1809–1811 | 2 | Tennessee | Democratic-Republican | 1772–1822 |
| Washington C. Whitthorne | 1886–1887 | 1 | Tennessee | Democratic | 1825–1891 |
| William Pinkney Whyte | 1868–1869 1875–1881 1906–1908 | 1, 3 | Maryland | Democratic | 1824–1908 |
| Louis Wigfall | 1859–1861 | 1 | Texas | Democratic | 1816–1874 |
| Leonard Wilcox | 1842–1843 | 3 | New Hampshire | Democratic | 1799–1850 |
| Alexander Wiley | 1939–1963 | 3 | Wisconsin | Republican | 1884–1967 |
| Xenophon P. Wilfley | 1918 | 3 | Missouri | Democratic | 1871–1931 |
| William Wilkins | 1831–1834 | 3 | Pennsylvania | Democratic | 1779–1865 |
| Morton S. Wilkinson | 1859–1865 | 2 | Minnesota | Republican | 1819–1894 |
| Calvin Willey | 1825–1831 | 3 | Connecticut | National Republican | 1776–1858 |
| Waitman T. Willey | 1861–1863 1863–1871 | 2 | Virginia West Virginia | Union Republican | 1811–1900 |
| Abram Williams | 1886–1887 | 1 | California | Republican | 1832–1911 |
| George Henry Williams | 1865–1871 | 2 | Oregon | Republican | 1823–1910 |
| George Howard Williams | 1925–1926 | 3 | Missouri | Republican | 1871–1963 |
| Harrison A. Williams | 1959–1982 | 1 | New Jersey | Democratic | 1919–2001 |
| Jared W. Williams | 1853–1854 | 2 | New Hampshire | Democratic | 1796–1864 |
| John Williams | 1815–1823 | 2 | Tennessee | Democratic-Republican | 1778–1837 |
| John J. Williams | 1947–1970 | 1 | Delaware | Republican | 1904–1988 |
| John Sharp Williams | 1911–1923 | 1 | Mississippi | Democratic | 1854–1932 |
| John Stuart Williams | 1879–1885 | 3 | Kentucky | Democratic | 1818–1898 |
| Reuel Williams | 1837–1843 | 1 | Maine | Democratic | 1783–1862 |
| Thomas Hickman Williams | 1838–1839 | 1 | Mississippi | Democratic | 1801–1851 |
| Thomas Hill Williams | 1817–1824 1824–1829 | 2 | Mississippi | Democratic-Republican Democratic | 1780–1840 |
| Ben M. Williamson | 1930–1931 | 2 | Kentucky | Democratic | 1864–1941 |
| Frank B. Willis | 1921–1928 | 3 | Ohio | Republican | 1871–1928 |
| Raymond E. Willis | 1941–1947 | 3 | Indiana | Republican | 1875–1956 |
| David Wilmot | 1861–1863 | 1 | Pennsylvania | Republican | 1814–1868 |
| Ephraim King Wilson II | 1885–1891 | 3 | Maryland | Democratic | 1821–1891 |
| George A. Wilson | 1943–1949 | 2 | Iowa | Republican | 1884–1953 |
| Henry Wilson | 1855 1855–1856 1856–1873 | 2 | Massachusetts | Free Soil American Republican | 1812–1875 |
| James F. Wilson | 1883–1895 | 2 | Iowa | Republican | 1828–1895 |
| James J. Wilson | 1815–1821 | 1 | New Jersey | Democratic-Republican | 1775–1824 |
| John L. Wilson | 1895–1899 | 1 | Washington | Republican | 1850–1912 |
| Pete Wilson | 1983–1991 | 1 | California | Republican | 1933–present |
| Robert Wilson | 1862–1863 | 3 | Missouri | Union | 1803–1870 |
| William Windom | 1870–1871 1871–1881 1881–1883 | 2 | Minnesota | Republican | 1827–1891 |
| Paine Wingate | 1789–1793 | 2 | New Hampshire | Democratic-Republican | 1739–1838 |
| Robert Charles Winthrop | 1850–1851 | 1 | Massachusetts | Whig | 1809–1894 |
| Tim Wirth | 1987–1993 | 3 | Colorado | Democratic | 1939–present |
| Garrett Withers | 1949–1950 | 3 | Kentucky | Democratic | 1884–1953 |
| Robert E. Withers | 1875–1881 | 1 | Virginia | Democratic | 1821–1907 |
| Harris Wofford | 1991–1995 | 1 | Pennsylvania | Democratic | 1926–2019 |
| Thomas A. Wofford | 1956 | 2 | South Carolina | Democratic | 1908–1978 |
| Edward O. Wolcott | 1889–1901 | 2 | Colorado | Republican | 1848–1905 |
| Josiah O. Wolcott | 1917–1921 | 1 | Delaware | Democratic | 1877–1938 |
| William Woodbridge | 1841–1847 | 2 | Michigan | Whig | 1780–1861 |
| Levi Woodbury | 1825–1831 1841–1845 | 2, 3 | New Hampshire | Democratic | 1789–1851 |
| John D. Works | 1911–1917 | 1 | California | Republican | 1847–1928 |
| Thomas Worthington | 1803–1807 1810–1814 | 1, 3 | Ohio | Democratic-Republican | 1773–1827 |
| George G. Wright | 1871–1877 | 2 | Iowa | Republican | 1820–1896 |
| Joseph A. Wright | 1862–1863 | 1 | Indiana | Democratic | 1810–1867 |
| Robert Wright | 1801–1806 | 3 | Maryland | Democratic-Republican | 1752–1826 |
| Silas Wright | 1833–1844 | 3 | New York | Democratic | 1795–1847 |
| William Wright | 1853–1859 1863–1866 | 1, 2 | New Jersey | Democratic | 1794–1866 |
| Louis C. Wyman | 1974–1975 | 3 | New Hampshire | Republican | 1917–2002 |
| Ralph Yarborough | 1957–1971 | 1 | Texas | Democratic | 1903–1996 |
| Richard Yates | 1865–1871 | 2 | Illinois | Republican | 1815–1873 |
| Lafayette Young | 1910–1911 | 2 | Iowa | Republican | 1848–1926 |
| Milton Young | 1945–1981 | 3 | North Dakota | Republican | 1897–1983 |
| Richard M. Young | 1837–1843 | 3 | Illinois | Democratic | 1798–1861 |
| Stephen M. Young | 1959–1971 | 1 | Ohio | Democratic | 1889–1984 |
| David Levy Yulee | 1845–1851 1855–1861 | 1, 3 | Florida | Democratic | 1810–1886 |
| Edward Zorinsky | 1976–1987 | 1 | Nebraska | Democratic | 1928–1987 |