# List of special elections to the United States Senate

Special elections to the United States Senate are held to fill the vacancies that occur when a senator dies or resigns before the completion of their six-year term. Winners of these special elections typically serve the remainder of the term of the senator who has caused the vacancy. General elections to the U.S. Congress are held in November of even-numbered years. New Congresses convened on March 4 of the following year until 1934, and since then, new Congresses have begun on January 3 of the following year.
Because of the cost of conducting a special election, most states hold elections to fill a Senate vacancy in conjunction with the next general election, while some states, such as Alabama and Texas, allow for special elections to the Senate to be held before a general election (similar to special elections to the U.S. House of Representatives, though special elections are on a state-wide basis). Special elections can alter the balance of power in the Senate, as can temporary appointments.

## Appointments by governors

Prior to ratification of the Seventeenth Amendment to the United States Constitution in 1913, most state legislatures elected senators (Sen.), as well as replacement senators. Some states empowered their governor to make temporary appointments until the legislature was in session.
The Seventeenth Amendment now requires the governor (Gov.) of the state to issue a writ for a special election to fill a vacant Senate seat, but no timeframe is specified in the provision for when the special election is to be held. State legislatures may also empower the governor to fill a vacancy by a temporary appointment until the winner of the special election is certified. The constitution does not set out how the temporary appointee is to be selected (e.g., there is no federal requirement that the appointee be of the same party, as happened most recently in New Jersey in 2013), and the state legislature can legislate as to how the replacement is to be selected.
North Dakota, Oregon and Wisconsin do not empower their governor to make temporary appointments and require special elections. Between 2004 and 2008, Massachusetts denied the power of the governor to appoint a replacement; in 2004, the Democratic-controlled legislature wanted to limit the power of the Republican governor (Gov. Mitt Romney) to appoint a successor to then-senator John Kerry if he were elected president that year. With the death of Sen. Ted Kennedy, the legislature chose to revert the rules to allow the Democratic governor (Gov. Deval Patrick) to appoint a temporary replacement senator while awaiting the results of a special election to complete the existing term. Hawaii allows the governor to appoint an interim senator "who serves until the next regularly-scheduled general election, chosen from a list of three prospective appointees that the prior incumbent's political party submits". Alaska in 2004 enacted conflicting legislation and a separate ballot referendum law that took effect on the same day. It is uncertain if the Alaska governor may successfully appoint an interim senator to serve until the mandated special election occurs 60 to 90 days after the vacancy happens. The ballot-approved law fails to specifically authorize the governor to appoint, though the legislative law does. Since 2021, Oklahoma permits its governor again to appoint a successor who is of the same party as the previous senator for at least the preceding five years when the vacancy arises in an even-numbered year, only after the appointee has taken an oath not to run in either a regular or special Senate election.

## List of special elections

This is an incomplete list of special elections to the United States Senate. The list only includes vacancies that were filled by special election. Not included are those situations in which vacancies were only filled by appointment or general election, or new seats.
* 1790
* 1800
* 1820
* 1830
* 1840
* 1850
* 1860
* 1870
* 1880
* 1890
* 1900
* 1910
* 1920
* 1930
* 1940
* 1950
* 1960
* 1970
* 1980
* 1990
* 2000
* 2010
* 2020
| State (Class) | Original | Original | Appointee | Appointee | Election winner | Election winner |
| State (Class) | Senator | Vacancy event | Senator | Date | Senator | Date |
| Virginia (Class 1) | William Grayson (AA) | Died March 12, 1790 | John Walker (PA) | March 31, 1790 | James Monroe (AA) | November 9, 1790 |
| New Jersey (Class 2) | William Paterson (PA) | Resigned November 13, 1790 | No appointment | No appointment | Philemon Dickinson (PA) | November 23, 1790 |
| Connecticut (Class 3) | William S. Johnson (PA) | Resigned March 4, 1791 | No appointment | No appointment | Roger Sherman (PA) | June 13, 1791 |
| Virginia (Class 2) | Richard Henry Lee (AA) | Resigned October 8, 1792 | No appointment | No appointment | John Taylor (AA) | October 18, 1792 |
| Maryland (Class 1) | Charles Carroll (PA) | Resigned November 30, 1792 | No appointment | No appointment | Richard Potts (PA) | January 10, 1793 |
| Pennsylvania (Class 1) | Vacant | Failure to elect by March 4, 1791 | No appointment | No appointment | Albert Gallatin (AA) | February 28, 1793 |
| Connecticut (Class 3) | Roger Sherman (PA) | Died July 23, 1793 | No appointment | No appointment | Stephen Mitchell (PA) | December 2, 1793 |
| New York (Class 3) | Rufus King (F) | Resigned May 23, 1796 | No appointment | No appointment | John Laurance (F) | November 9, 1796 |
| New York (Class 1) | Philip Schuyler (F) | Resigned January 3, 1798 | No appointment | No appointment | John Sloss Hobart (F) | January 11, 1798 |
| New York (Class 1) | John Sloss Hobart (F) | Resigned April 16, 1798 | William North (F) | May 5, 1798 | James Watson (F) | August 17, 1798 |
| New York (Class 1) | James Watson (F) | Resigned March 19, 1800 | No appointment | No appointment | Gouverneur Morris (F) | April 3, 1800 |
| New York (Class 3) | John Laurance (F) | Resigned August 1800 | No appointment | No appointment | John Armstrong Jr. (DR) | November 6, 1800 |
| New York (Class 3) | John Armstrong Jr. (DR) | Resigned February 5, 1802 | No appointment | No appointment | DeWitt Clinton (DR) | February 9, 1802 |
| New York (Class 1) | Theodorus Bailey (DR) | Resigned January 16, 1804 | No appointment | No appointment | John Armstrong Jr. (DR) | February 3, 1804 |
| New York (Class 3) | John Armstrong Jr. (DR) | Resigned February 23, 1804 | No appointment | No appointment | John Smith (DR) | February 3, 1804 |
| New York (Class 1) | John Armstrong Jr. (DR) | Resigned June 30, 1804 | No appointment | No appointment | Samuel L. Mitchill (DR) | November 9, 1804 |
| Alabama (Class 3) | John Williams Walker (DR) | Resigned December 12, 1822 | No appointment | No appointment | William Kelly (DR) | December 12, 1822 |
| Delaware (Class 2) | Nicholas Van Dyke (F) | Failure to elect by March 4, 1823 | No appointment | No appointment | Nicholas Van Dyke (F) | January 8, 1824 |
| Delaware (Class 1) | Caesar A. Rodney (DR) | Resigned January 29, 1823 | No appointment | No appointment | Thomas Clayton (F) | January 8, 1824 |
| Louisiana (Class 3) | James Brown (DR) | Resigned December 10, 1823 | No appointment | No appointment | Josiah S. Johnston (DR) | January 15, 1824 |
| Louisiana (Class 2) | Henry Johnson (DR) | Resigned May 27, 1824 | No appointment | No appointment | Charles Bouligny (DR) | November 19, 1824 |
| Illinois (Class 3) | Ninian Edwards (DR) | Resigned March 4, 1824 | No appointment | No appointment | John McLean (DR) | November 24, 1824 |
| Georgia (Class 2) | Nicholas Ware (DR) | Died January 29, 1823 | No appointment | No appointment | Thomas W. Cobb (F) | December 6, 1824 |
| Virginia (Class 2) | John Taylor (DR) | Died August 21, 1824 | No appointment | No appointment | Littleton Tazewell (DR) | December 7, 1824 |
| Alabama (Class 3) | Henry H. Chambers (DR) | Died January 24, 1826 | Israel Pickens (DR) | February 17, 1826 | John McKinley (J) | November 27, 1826 |
| New York (Class 1) | Martin Van Buren (DR) | Resigned December 20, 1828 | No appointment | No appointment | Charles E. Dudley (D) | January 15, 1829 |
| New York (Class 3) | William L. Marcy (D) | Resigned January 1, 1833 | No appointment | No appointment | Silas Wright (D) | January 4, 1833 |
| Alabama (Class 3) | John McKinley (D) | Resigned April 22, 1837 | Clement Comer Clay (D) | June 19, 1837 | Arthur P. Bagby (D) | November 24, 1841 |
| Arkansas (Class 2) | William S. Fulton (D) | Died August 15, 1844 | No appointment | No appointment | Chester Ashley (D) | November 8, 1844 |
| New York (Class 1) | Nathaniel P. Tallmadge (W) | Resigned June 17, 1844 | Daniel S. Dickinson (D) | November 30, 1844 | Daniel S. Dickinson (D) | January 18, 1845 |
| New York (Class 3) | Silas Wright (D) | Resigned November 26, 1844 | Henry A. Foster (D) | November 30, 1844 | John Adams Dix (D) | January 18, 1845 |
| Arkansas (Class 2) | Chester Ashley (D) | Died April 29, 1848 | William K. Sebastian (D) | May 12, 1848 | William K. Sebastian (D) | November 17, 1848 |
| Alabama (Class 2) | Dixon Hall Lewis (D) | Died October 24, 1848 | Benjamin Fitzpatrick (D) | November 25, 1848 | Jeremiah Clemens (D) | November 30, 1849 |
| Massachusetts (Class 2) | Daniel Webster (W) | Resigned July 22, 1850 | Robert Charles Winthrop (W) | July 30, 1850 | Robert Rantoul Jr. (D) | January 14, 1851 |
| New Hampshire (Class 3) | James Bell (R) | Died May 26, 1857 | No appointment | No appointment | Daniel Clark (R) | June 26, 1857 |
| Tennessee (Class 1) | Vacant | Failure to elect by March 4, 1857 | No appointment | No appointment | Andrew Johnson (D) | October 8, 1857 |
| South Carolina (Class 3) | Andrew Butler | Died May 25, 1857 | No appointment | No appointment | James Henry Hammond (D) | December 6, 1857 |
| North Carolina (Class 3) | Asa Biggs | Resigned May 5, 1858 | Thomas Lanier Clingman (D) | May 7, 1858 | Thomas Lanier Clingman (D) | November 23, 1858 |
| California (Class 3) | David C. Broderick (D) | Died September 16, 1859 | Henry P. Haun (D) | November 3, 1859 | Milton S. Latham (D) | January 11, 1860 |
| California (Class 1) | Eugene Casserly (D) | Resigned November 29, 1873 | No appointment | No appointment | John S. Hager (D) | December 23, 1873 |
| Alabama (Class 3) | George S. Houston (D) | Died December 31, 1879 | Luke Pryor (D) | January 7, 1880 | James L. Pugh (D) | November 24, 1880 |
| New York (Class 1) | Thomas C. Platt (R) | Resigned May 16, 1881 | No appointment | No appointment | Warner Miller (R) | July 16, 1881 |
| New York (Class 3) | Roscoe Conkling (R) | Resigned May 16, 1881 | No appointment | No appointment | Elbridge G. Lapham (R) | July 22, 1881 |
| Arkansas (Class 2) | Augustus Garland (D) | Resigned March 6, 1885 | No appointment | No appointment | James H. Berry (D) | March 20, 1885 |
| California (Class 1) | John Franklin Miller (R) | Died March 8, 1886 | George Hearst (D) | March 23, 1886 | Abram P. Williams (R) | August 4, 1886 |
| California (Class 1) | George Hearst (D) | Died February 28, 1891 | No appointment | No appointment | Charles N. Felton (R) | March 19, 1891 |
| California (Class 3) | Leland Stanford (R) | Died June 21, 1893 | George C. Perkins (R) | July 26, 1893 | George C. Perkins (R) | January 22, 1895 |
| Mississippi (Class 2) | Edward C. Walthall (D) | Resigned January 24, 1894 | No appointment | No appointment | Anselm J. McLaurin (D) | February 7, 1894 |
| Louisiana (Class 3) | Edward D. White (D) | Resigned March 12, 1894 | Newton C. Blanchard (D) | March 12, 1894 | Newton C. Blanchard (D) | May 16, 1894 |
| Georgia (Class 2) | Alfred H. Colquitt (D) | Died March 26, 1894 | Patrick Walsh (D) | April 2, 1894 | Patrick Walsh (D) | November 2, 1894 |
| North Carolina (Class 3) | Zebulon B. Vance | Died April 14, 1894 | Thomas J. Jarvis (D) | April 19, 1894 | Jeter C. Pritchard (D) | January 23, 1895 |
| Michigan (Class 1) | Francis B. Stockbridge (R) | Died April 3, 1894 | John Patton Jr. (R) | May 5, 1894 | Julius C. Burrows (R) | January 24, 1895 |
| Montana (Class 1) | Vacant | Failure to elect by March 4, 1893 | No appointment | No appointment | Lee Mantle (R) | January 16, 1895 |
| Wyoming (Class 1) | Vacant | Failure to elect by March 4, 1893 | No appointment | No appointment | Clarence D. Clark (R) | January 23, 1895 |
| Washington (Class 1) | Vacant | Failure to elect by March 4, 1893 | No appointment | No appointment | John L. Wilson (R) | February 19, 1895 |
| Mississippi (Class 2) | Edward C. Walthall (D) | Died April 21, 1898 | William V. Sullivan (D) | May 31, 1898 | William V. Sullivan (D) | January 16, 1900 |
| Alabama (Class 3) | Edmund Pettus (D) | Died July 27, 1907 | No appointment | No appointment | Joseph F. Johnston (D) | August 6, 1907 |
| Pennsylvania (Class 1) | Philander C. Knox (R) | Resigned March 4, 1909 | No appointment | No appointment | George T. Oliver (R) | March 17, 1909 |
| Mississippi (Class 2) | Anselm J. McLaurin (D) | Died December 22, 1909 | James Gordon (D) | December 27, 1909 | LeRoy Percy (D) | February 22, 1910 |
| Louisiana (Class 3) | Samuel D. McEnery (D) | Died June 28, 1910 | John Thornton (D) | August 27, 1910 | John Thornton (D) | December 6, 1910 |
| North Dakota (Class 3) | Martin N. Johnson (R) | Died October 12, 1909 | Fountain L. Thompson (D) | November 10, 1909 – Jan. 31, 1910 (resigned) | Asle Gronna (R) | February 1, 1911 |
| North Dakota (Class 3) | Martin N. Johnson (R) | Died October 12, 1909 | William E. Purcell (D) | February 1, 1910 | Asle Gronna (R) | February 1, 1911 |
| West Virginia (Class 2) | Stephen Benton Elkins (R) | Died January 4, 1911 | Davis Elkins (R) | January 9, 1911 | Clarence Wayland Watson (D) | February 1, 1911 |
| Iowa (Class 3) | Jonathan P. Dolliver (R) | Died October 15, 1910 | Lafayette Young (R) | November 4, 1910 | William S. Kenyon (R) | April 11, 1911 |
| Georgia (Class 3) | Alexander S. Clay (D) | Died November 13, 1910 | Joseph M. Terrell (D) | November 17, 1910 | M. Hoke Smith (D) | July 12, 1911 |
| Maine (Class 2) | William P. Frye (R) | Died August 8, 1911 | No appointment | No appointment | Obadiah Gardner (D) | April 2, 1912 |
| Colorado (Class 3) | Charles J. Hughes Jr. (D) | Died January 11, 1911 | No appointment | No appointment | Charles S. Thomas (D) | January 15, 1913 |
| Tennessee (Class 2) | Robert Love Taylor (D) | Died March 31, 1912 | Newell Sanders (R) | April 11, 1912 | William R. Webb (D) | January 23, 1913 |
| Nevada (Class 1) | George S. Nixon (R) | Died June 5, 1912 | William A. Massey (R) | July 1, 1912 | Key Pittman (D) | January 23, 1913 |
| Texas (Class 2) | Joseph Weldon Bailey (D) | Resigned January 3, 1913 | Rienzi Melville Johnston (D) | January 4, 1913 | Morris Sheppard (D) | January 23, 1913 |
| Arkansas (Class 2) | Jeff Davis | Died January 3, 1913 | John N. Heiskell (D) | January 6, 1913 | William Marmaduke Kavanaugh (D) | January 23, 1913 |
| Idaho (Class 3) | Weldon B. Heyburn (R) | Died October 17, 1912 | Kirtland Irving Perky (D) | November 18, 1912 | James H. Brady (R) | January 24, 1913 |
| Illinois (Class 3) | William Lorimer (R) | Election invalidated July 13, 1912 | No appointment | No appointment | Lawrence Yates Sherman (R) | March 26, 1913 |
| Seventeenth Amendment ratified April 8, 1913. All subsequent Senate elections are by popular vote. |||||||
| Maryland (Class 1) | Isidor Rayner (D) | Died November 25, 1912 | William P. Jackson (R) | November 29, 1912 | Blair Lee (D) | November 4, 1913 |
| Alabama (Class 3) | Joseph F. Johnston (D) | Died August 8, 1913 | No appointment | No appointment | Francis S. White (D) | May 11, 1914 |
| Georgia (Class 2) | Augustus Octavius Bacon (D) | Died February 14, 1914 | William S. West (D) | March 1, 1914 | Thomas W. Hardwick (D) | November 3, 1914 |
| Kentucky (Class 3) | William O. Bradley (R) | Died May 23, 1914 | Johnson N. Camden (D) | June 16, 1914 | Johnson N. Camden (D) | November 3, 1914 |
| Maine (Class 2) | Edwin C. Burleigh (R) | Died June 16, 1916 | No appointment | No appointment | Bert M. Fernald (R) | September 11, 1916 |
| Indiana (Class 3) | Benjamin F. Shively (D) | Died March 14, 1916 | Thomas Taggart (D) | March 20, 1916 | James Eli Watson (R) | November 7, 1916 |
| Arkansas (Class 3) | James Paul Clarke (D) | Died October 1, 1916 | No appointment | No appointment | William F. Kirby (D) | November 7, 1916 |
| Wisconsin (Class 3) | Paul O. Husting (D) | Died October 21, 1917 | No appointment | No appointment | Irvine L. Lenroot (R) | April 18, 1918 |
| Oregon (Class 2) | Harry Lane (D) | Died May 23, 1917 | Charles L. McNary (R) | May 29, 1917 | Frederick W. Mulkey (R) | November 5, 1918 |
| Nevada (Class 3) | Francis G. Newlands (D) | Died December 24, 1917 | Charles B. Henderson (D) | January 12, 1918 | Charles B. Henderson (D) | November 5, 1918 |
| Idaho (Class 3) | James H. Brady (R) | Died January 13, 1918 | John F. Nugent (D) | January 22, 1918 | John F. Nugent (D) | November 5, 1918 |
| New Jersey (Class 2) | William Hughes (D) | Died January 30, 1918 | David Baird (R) | February 23, 1918 | David Baird (R) | November 5, 1918 |
| Louisiana (Class 3) | Robert F. Broussard (D) | Died April 12, 1918 | Walter Guion (D) | April 22, 1918 | Edward Gay (D) | November 5, 1918 |
| Missouri (Class 3) | William J. Stone (D) | Died April 14, 1918 | Xenophon P. Wilfley (D) | April 30, 1918 | Selden P. Spencer (R) | November 5, 1918 |
| South Carolina (Class 2) | Benjamin R. Tillman (D) | Died July 3, 1918 | Christie Benet (D) | July 6, 1918 | William P. Pollock (D) | November 5, 1918 |
| New Hampshire (Class 3) | Jacob H. Gallinger (R) | Died August 17, 1918 | Irving W. Drew (R) | September 2, 1918 | George H. Moses (R) | November 5, 1918 |
| Virginia (Class 2) | Thomas S. Martin (D) | Died November 12, 1919 | Carter Glass (D) | November 18, 1919 | Carter Glass (D) | November 2, 1920 |
| Alabama (Class 3) | John H. Bankhead (D) | Died March 1, 1920 | B. B. Comer (D) | March 5, 1920 | J. Thomas Heflin (D) | November 2, 1920 |
| New Mexico (Class 2) | Albert B. Fall (R) | Resigned March 3, 1921 | Holm O. Bursum (R) | March 11, 1921 | Holm O. Bursum (D) | September 20, 1921 |
| Delaware (Class 1) | Josiah O. Wolcott (D) | Resigned July 2, 1921 | T. Coleman du Pont (R) | July 7, 1921 | Thomas F. Bayard Jr. (D) | November 7, 1922 |
| Pennsylvania (Class 1) | Philander C. Knox (R) | Died October 12, 1921 | William E. Crow (R) | October 17, 1921 – August 2, 1922 (died) | David A. Reed (R) | November 7, 1922 |
| Pennsylvania (Class 1) | Philander C. Knox (R) | Died October 12, 1921 | David A. Reed (R) | August 8, 1922 | David A. Reed (R) | November 7, 1922 |
| Pennsylvania (Class 3) | Boies Penrose (R) | Died December 31, 1921 | George W. Pepper (R) | January 9, 1922 | George W. Pepper (R) | November 7, 1922 |
| Iowa (Class 2) | William S. Kenyon (R) | Resigned February 24, 1922 | Charles A. Rawson (R) | February 24, 1922 | Smith W. Brookhart (R) | November 7, 1922 |
| Georgia (Class 3) | Thomas E. Watson (D) | Died September 26, 1922 | Rebecca Felton (D) | November 21, 1922 | Walter F. George (D) | November 7, 1922 |
| Colorado (Class 2) | Samuel D. Nicholson (R) | Died March 24, 1923 | Alva B. Adams (D) | May 17, 1923 | Rice W. Means (R) | November 4, 1924 |
| Connecticut (Class 3) | Frank B. Brandegee (R) | Died October 14, 1924 | No appointment | No appointment | Hiram Bingham III (R) | December 16, 1924 |
| Idaho (Class 3) | Frank Gooding (R) | Died June 24, 1928 | John Thomas (D) | June 30, 1928 | John Thomas (R) | November 6, 1928 |
| Ohio (Class 3) | Frank B. Willis (R) | Died March 30, 1928 | Cyrus Locher (D) | April 5, 1928 | Theodore E. Burton (R) | November 6, 1928 |
| Ohio (Class 3) | Theodore E. Burton (R) | Died October 28, 1929 | Roscoe C. McCulloch (R) | November 5, 1929 | Robert J. Bulkley (D) | November 4, 1930 |
| Arkansas (Class 3) | Thaddeus H. Caraway (D) | Died November 6, 1931 | Hattie Caraway (D) | December 9, 1931 | Hattie Caraway (D) | January 12, 1932 |
| New Jersey (Class 2) | Dwight Morrow (R) | Died October 5, 1931 | William Warren Barbour (R) | December 1, 1931 | William Warren Barbour (R) | November 8, 1932 |
| Georgia (Class 3) | William J. Harris (D) | Died April 18, 1932 | John S. Cohen (D) | April 25, 1932 | Richard Russell Jr. (D) | November 8, 1932 |
| Vermont (Class 3) | Porter H. Dale (R) | Died October 6, 1933 | Ernest W. Gibson (R) | November 21, 1933 | Ernest W. Gibson (R) | January 16, 1934 |
| Montana (Class 3) | Thomas J. Walsh (D) | Died March 4, 1933 | John E. Erickson (D) | March 13, 1933 | James E. Murray (D) | November 6, 1934 |
| Tennessee (Class 2) | Cordell Hull (D) | Resigned March 4, 1933 | Nathan L. Bachman (D) | March 4, 1933 | Nathan L. Bachman (D) | November 6, 1934 |
| New Mexico (Class 2) | Sam G. Bratton (D) | Resigned June 24, 1933 | Carl A. Hatch (D) | October 10, 1933 | Carl A. Hatch (D) | November 6, 1934 |
| Louisiana (Class 2) | Huey Long (D) | Died September 10, 1935 | Rose Long (D) | January 31, 1936 | Rose Long (D) | April 21, 1936 |
| Florida (Class 1) | Park Trammell | Died May 8, 1936 | Scott Loftin (D) | May 26, 1936 | Charles O. Andrews (D) | November 3, 1936 |
| Florida (Class 3) | Duncan U. Fletcher | Died June 17, 1936 | William Luther Hill (D) | July 1, 1936 | Claude Pepper (D) | November 3, 1936 |
| Arkansas (Class 3) | Joseph T. Robinson (D) | Died July 14, 1937 | No appointment | No appointment | John E. Miller (ID) | November 15, 1937 |
| Alabama (Class 3) | Hugo Black (D) | Resigned August 19, 1937 | Dixie Graves (D) | August 20, 1937 – Jan. 10, 1938 (resigned) | Lister Hill (D) | April 26, 1938 |
| Alabama (Class 3) | Hugo Black (D) | Resigned August 19, 1937 | Lister Hill (D) | January 11, 1938 | Lister Hill (D) | April 26, 1938 |
| Tennessee (Class 2) | Nathan L. Bachman (D) | Died April 23, 1937 | George L. Berry (D) | May 6, 1937 | Tom Stewart (D) | April 26, 1938 |
| New York (Class 1) | Royal Copeland (D) | Died June 17, 1938 | No appointment | No appointment | James M. Mead (D) | November 8, 1938 |
| South Dakota (Class 3) | Herbert E. Hitchcock (D) | Resigned November 8, 1938 | No appointment | No appointment | Gladys Pyle (R) | November 9, 1938 |
| Texas (Class 2) | Morris Sheppard (D) | Died April 9, 1941 | Andrew Houston (D) | April 21, 1941 | W. Lee O'Daniel (D) | June 28, 1941 |
| Mississippi (Class 2) | Pat Harrison (D) | Died June 22, 1941 | James Eastland (D) | June 30, 1941 | Wall Doxey (D) | September 23, 1941 |
| South Carolina (Class 2) | James F. Byrnes (D) | Resigned July 17, 1941 | Alva Lumpkin (D) | July 22, 1941 – August 1, 1941 (died) | Burnet Maybank (D) | November 5, 1941 |
| South Carolina (Class 2) | James F. Byrnes (D) | Resigned July 17, 1941 | Roger Peace (D) | August 5, 1941 | Burnet Maybank (D) | November 5, 1941 |
| Colorado (Class 3) | Alva B. Adams (D) | Died December 1, 1941 | Eugene Millikin (R) | December 20, 1941 | Eugene Millikin (R) | November 3, 1942 |
| West Virginia (Class 2) | Matthew M. Neely (D) | Resigned January 12, 1941 | Joseph Rosier (D) | January 13, 1941 | Hugh Ike Shott (R) | November 3, 1942 |
| Nevada (Class 1) | Key Pittman (D) | Died November 10, 1940 | Berkeley Bunker (D) | November 27, 1940 | James G. Scrugham (D) | November 3, 1942 |
| Indiana (Class 3) | Frederick Van Nuys (D) | Died January 25, 1944 | Samuel D. Jackson (D) | January 28, 1944 | William E. Jenner (R) | November 7, 1944 |
| Oregon (Class 2) | Charles L. McNary (R) | Died February 25, 1944 | Guy Cordon (R) | March 4, 1944 | Guy Cordon (R) | November 7, 1944 |
| New Jersey (Class 1) | William Warren Barbour (R) | Died November 22, 1943 | Arthur Walsh (D) | November 26, 1943 | H. Alexander Smith (R) | November 7, 1944 |
| Massachusetts (Class 2) | Henry Cabot Lodge Jr. (R) | Resigned February 3, 1944 | Sinclair Weeks (R) | February 8, 1944 | Leverett Saltonstall (R) | November 7, 1944 |
| North Dakota (Class 2) | John Moses (D) | Died March 3, 1945 | Milton Young (R) | March 12, 1945 | Milton Young (R) | June 25, 1946 |
| Alabama (Class 2) | John H. Bankhead II (D) | Died June 12, 1946 | George R. Swift (D) | June 15, 1946 | John Sparkman (D) | November 5, 1946 |
| California (Class 1) | Hiram Johnson (R) | Died August 6, 1945 | William F. Knowland (R) | August 26, 1945 | William F. Knowland (R) | November 5, 1946 |
| Connecticut (Class 1) | Francis T. Maloney (D) | Died January 16, 1945 | Thomas C. Hart (R) | February 15, 1945 | Raymond E. Baldwin (R) | November 5, 1946 |
| Idaho (Class 2) | John Thomas (R) | Died November 10, 1945 | Charles C. Gossett (D) | November 17, 1945 | Henry Dworshak (R) | November 5, 1946 |
| Kentucky (Class 2) | Happy Chandler (D) | Resigned November 1, 1945 | William A. Stanfill (R) | November 19, 1945 | John Sherman Cooper (R) | November 5, 1946 |
| Ohio (Class 1) | Harold H. Burton (R) | Resigned September 30, 1945 | James W. Huffman (D) | October 8, 1945 | Kingsley A. Taft (R) | November 5, 1946 |
| Virginia (Class 2) | Carter Glass (D) | Died May 28, 1946 | Thomas G. Burch (D) | May 31, 1946 | A. Willis Robertson (D) | November 5, 1946 |
| Mississippi (Class 1) | Theodore G. Bilbo (D) | Died August 24, 1947 | No appointment | No appointment | John C. Stennis (D) | November 5, 1947 |
| New York (Class 3) | Robert F. Wagner (D) | Resigned June 28, 1949 | John Foster Dulles (R) | July 7, 1949 | Herbert H. Lehman (D) | November 8, 1949 |
| North Carolina (Class 2) | J. Melville Broughton (D) | Died March 6, 1949 | Frank Porter Graham (D) | March 29, 1949 | Willis Smith (D) | November 7, 1950 |
| Kansas (Class 3) | Clyde M. Reed (R) | Died November 8, 1949 | Harry Darby (R) | December 2, 1949 | Frank Carlson (R) | November 7, 1950 |
| Idaho (Class 2) | Bert H. Miller (D) | Died October 8, 1949 | Henry Dworshak (R) | October 14, 1949 | Henry Dworshak (R) | November 7, 1950 |
| Connecticut (Class 3) | Brien McMahon (D) | Died July 28, 1952 | William A. Purtell (R) | August 29, 1952 | Prescott Bush (R) | November 4, 1952 |
| Kentucky (Class 2) | Virgil Chapman (D) | Died March 8, 1951 | Thomas R. Underwood (D) | March 19, 1951 | John Sherman Cooper (R) | November 4, 1952 |
| Michigan (Class 1) | Arthur Vandenberg (R) | Died April 18, 1951 | Blair Moody (D) | April 23, 1951 | Charles E. Potter (R) | November 4, 1952 |
| Nebraska (Class 2) | Kenneth S. Wherry (R) | Died November 29, 1951 | Fred A. Seaton (R) | December 10, 1951 | Dwight Griswold (R) | November 4, 1952 |
| California (Class 3) | Richard Nixon (R) | Resigned January 1, 1953 Elected as vice president | Thomas Kuchel (R) | January 2, 1953 | Thomas Kuchel (R) | November 2, 1954 |
| North Carolina (Class 2) | Willis Smith (D) | Died June 26, 1953 | Alton Lennon (D) | July 15, 1953 | Kerr Scott (D) | November 2, 1954 |
| North Carolina (Class 3) | Clyde R. Hoey (D) | Died May 12, 1954 | Sam Ervin (D) | June 5, 1954 | Sam Ervin (D) | November 2, 1954 |
| Nebraska (Class 1) | Hugh Butler (R) | Died July 1, 1954 | Sam Reynolds (R) | July 7, 1954 | Roman Hruska (R) | November 2, 1954 |
| Nebraska (Class 2) | Dwight Griswold (R) | Died April 12, 1954 | Eva Bowring (R) | April 26, 1954 | Hazel Abel (R) | November 2, 1954 |
| Kentucky (Class 2) | Alben Barkley (D) | Died April 30, 1956 | Robert Humphreys (D) | June 25, 1956 | John Sherman Cooper (R) | November 6, 1956 |
| West Virginia (Class 1) | Harley M. Kilgore (D) | Died February 28, 1956 | William Laird III (D) | March 13, 1956 | Chapman Revercomb (R) | November 6, 1956 |
| South Carolina (Class 2) | Strom Thurmond (D) | Resigned April 4, 1956 | Thomas A. Wofford (D) | April 5, 1956 | Strom Thurmond (D) | November 6, 1956 |
| Texas (Class 1) | Price Daniel (D) | Resigned January 14, 1957 | William Blakley (D) | January 17, 1957 | Ralph Yarborough (D) | April 2, 1957 |
| Wisconsin (Class 1) | Joseph McCarthy (R) | Died May 2, 1957 | No appointment | No appointment | William Proxmire (D) | August 27, 1957 |
| West Virginia (Class 2) | Matthew M. Neely (D) | Died January 18, 1958 | John D. Hoblitzell Jr. (R) | January 25, 1958 | Jennings Randolph (D) | November 4, 1958 |
| North Carolina (Class 2) | W. Kerr Scott (D) | Died April 16, 1958 | B. Everett Jordan (D) | April 19, 1958 | B. Everett Jordan (D) | November 4, 1958 |
| North Dakota (Class 1) | William Langer (R) | Died November 8, 1959 | Clarence Brunsdale (R) | November 19, 1959 | Quentin Burdick (D-NPL) | June 28, 1960 |
| Missouri (Class 1) | Thomas C. Hennings Jr. (D) | Died September 13, 1960 | Edward V. Long (D) | September 23, 1960 | Edward V. Long (D) | November 8, 1960 |
| Oregon (Class 2) | Richard Neuberger (D) | Died March 9, 1960 | Hall Lusk (D) | March 16, 1960 | Maurine Neuberger (D) | November 8, 1960 |
| Texas (Class 2) | Lyndon Johnson (D) | Resigned January 3, 1961 Elected as vice president | William Blakley (D) | January 3, 1961 | John Tower (R) | May 27, 1961 |
| Massachusetts (Class 1) | John F. Kennedy (D) | Resigned December 22, 1960 Elected as president | Benjamin A. Smith II (D) | December 27, 1960 | Ted Kennedy (D) | November 6, 1962 |
| New Hampshire (Class 2) | Styles Bridges (R) | Died November 26, 1961 | Maurice J. Murphy Jr. (R) | December 7, 1961 | Thomas McIntyre (D) | November 6, 1962 |
| Kansas (Class 2) | Andrew Schoeppel (R) | Died January 21, 1962 | James Pearson (R) | January 31, 1962 | James Pearson (R) | November 6, 1962 |
| Idaho (Class 2) | Henry Dworshak (R) | Died July 23, 1962 | Len Jordan (R) | August 6, 1962 | Len Jordan (R) | November 6, 1962 |
| Wyoming (Class 2) | Edwin Keith Thomson (R) | Died December 9, 1960 | John J. Hickey (D) | January 3, 1961 | Milward Simpson (R) | November 6, 1962 |
| New Mexico (Class 1) | Dennis Chavez (D) | Died November 18, 1962 | Edwin Mechem (R) | November 30, 1962 | Joseph Montoya (D) | November 3, 1964 |
| Oklahoma (Class 2) | Robert S. Kerr (D) | Died January 1, 1963 | J. Howard Edmondson (D) | January 6, 1963 | Fred R. Harris (D) | November 3, 1964 |
| Tennessee (Class 2) | Estes Kefauver (D) | Died August 10, 1963 | Herbert Walters (D) | August 20, 1963 | Ross Bass (D) | November 3, 1964 |
| South Carolina (Class 3) | Olin Johnston (D) | Died April 18, 1965 | Donald Russell (D) | April 22, 1965 | Fritz Hollings (D) | November 8, 1966 |
| Virginia (Class 1) | Harry F. Byrd Sr. (D) | Resigned November 10, 1965 | Harry F. Byrd Jr. (D) | November 12, 1965 | Harry F. Byrd Jr. (D) | November 8, 1966 |
| Alaska (Class 2) | Bob Bartlett (D) | Died December 11, 1968 | Ted Stevens (R) | December 24, 1968 | Ted Stevens (R) | November 3, 1970 |
| Illinois (Class 3) | Everett Dirksen (R) | Died September 7, 1969 | Ralph Tyler Smith (R) | September 17, 1969 | Adlai Stevenson III (D) | November 3, 1970 |
| Vermont (Class 1) | Winston L. Prouty (R) | Died September 10, 1971 | Robert Stafford (R) | September 16, 1971 | Robert Stafford (R) | January 7, 1972 |
| Georgia (Class 2) | Richard Russell Jr. (D) | Died January 21, 1971 | David H. Gambrell (D) | February 1, 1971 | Sam Nunn (D) | November 7, 1972 |
| New Hampshire (Class 3) | Failure to elect by January 3, 1975 | Failure to elect by January 3, 1975 | Norris H. Cotton (R) | August 8, 1975 | John A. Durkin (D) | September 16, 1975 |
| Minnesota (Class 1) | Hubert Humphrey (D) | Died January 13, 1978 | Muriel Humphrey (D) | January 25, 1978 | David Durenberger (R) | November 7, 1978 |
| Alabama (Class 3) | James Allen (D) | Died June 1, 1978 | Maryon Pittman Allen (D) | June 8, 1978 | Donald Stewart (D) | November 7, 1978 |
| Washington (Class 1) | Henry M. Jackson (D) | Died September 1, 1983 | Daniel J. Evans (R) | September 8, 1983 | Daniel J. Evans (R) | November 8, 1983 |
| North Carolina (Class 3) | John Porter East (R) | Died June 29, 1986 | Jim Broyhill (R) | July 14, 1986 | Terry Sanford (D) | November 8, 1986 |
| Indiana (Class 3) | Dan Quayle (R) | Resigned January 3, 1989 Elected as vice president | Dan Coats (R) | January 3, 1989 | Dan Coats (R) | November 6, 1990 |
| Hawaii (Class 1) | Spark Matsunaga (D) | Died April 15, 1990 | Daniel Akaka (D) | May 16, 1990 | Daniel Akaka (D) | November 6, 1990 |
| Pennsylvania (Class 1) | H. John Heinz III (R) | Died April 4, 1991 | Harris Wofford (D) | May 9, 1991 | Harris Wofford (D) | November 5, 1991 |
| California (Class 1) | Pete Wilson (R) | Resigned January 7, 1991 | John Seymour (R) | January 10, 1991 | Dianne Feinstein (D) | November 3, 1992 |
| North Dakota (Class 1) | Quentin Burdick (D-NPL) | Died September 8, 1992 | Jocelyn Burdick (D-NPL) | September 16, 1992 | Kent Conrad (D-NPL) | December 4, 1992 |
| Texas (Class 1) | Lloyd Bentsen (D) | Resigned January 20, 1993 | Bob Krueger (D) | January 21, 1993 | Kay Bailey Hutchison (R) | June 5, 1993 |
| Tennessee (Class 2) | Al Gore (D) | Resigned January 3, 1993 Elected as vice president | Harlan Mathews (D) | January 3, 1993 | Fred Thompson (R) | November 8, 1994 |
| Oklahoma (Class 2) | David Boren (D) | Resigned November 15, 1994 | No appointment | No appointment | Jim Inhofe (R) | November 8, 1994 |
| Oregon (Class 3) | Bob Packwood (R) | Resigned October 1, 1995 | No appointment | No appointment | Ron Wyden (D) | January 30, 1996 |
| Kansas (Class 3) | Bob Dole (R) | Resigned June 11, 1996 | Sheila Frahm (R) | June 11, 1996 | Sam Brownback (R) | November 5, 1996 |
| Georgia (Class 3) | Paul Coverdell (R) | Died July 18, 2000 | Zell Miller (D) | July 24, 2000 | Zell Miller (D) | November 7, 2000 |
| Missouri (Class 1) | Mel Carnahan (D) | Died October 16, 2000 | Jean Carnahan (D) | January 3, 2001 | Jim Talent (R) | November 5, 2002 |
| Wyoming (Class 1) | Craig L. Thomas (R) | Died June 4, 2007 | John Barrasso (R) | June 25, 2007 | John Barrasso (R) | November 4, 2008 |
| Mississippi (Class 1) | Trent Lott (R) | Resigned December 18, 2007 | Roger Wicker (R) | December 31, 2007 | Roger Wicker (R) | November 4, 2008 |
| Massachusetts (Class 1) | Ted Kennedy (D) | Died August 25, 2009 | Paul G. Kirk (D) | September 24, 2009 | Scott Brown (R) | January 19, 2010 |
| Illinois (Class 3) | Barack Obama (D) | Resigned November 16, 2008 Elected as president | Roland Burris (D) | January 12, 2009 | Mark Kirk (R) | November 2, 2010 |
| Delaware (Class 2) | Joe Biden (D) | Resigned January 15, 2009 Elected as vice president | Ted Kaufman (D) | January 16, 2009 | Chris Coons (D) | November 2, 2010 |
| New York (Class 1) | Hillary Clinton (D) | Resigned January 21, 2009 | Kirsten Gillibrand (D) | January 27, 2009 | Kirsten Gillibrand (D) | November 2, 2010 |
| West Virginia (Class 1) | Robert Byrd (D) | Died June 28, 2010 | Carte Goodwin (D) | July 20, 2010 | Joe Manchin (D) | November 2, 2010 |
| Massachusetts (Class 2) | John Kerry (D) | Resigned February 1, 2013 | Mo Cowan (D) | February 1, 2013 | Ed Markey (D) | June 25, 2013 |
| New Jersey (Class 2) | Frank Lautenberg (D) | Died June 3, 2013 | Jeffrey Chiesa (R) | June 10, 2013 | Cory Booker (D) | October 16, 2013 |
| South Carolina (Class 3) | Jim DeMint (R) | Resigned January 1, 2013 | Tim Scott (R) | January 2, 2013 | Tim Scott (R) | November 4, 2014 |
| Hawaii (Class 3) | Daniel Inouye (D) | Died December 17, 2012 | Brian Schatz (D) | December 26, 2012 | Brian Schatz (D) | November 4, 2014 |
| Oklahoma (Class 3) | Tom Coburn (R) | Resigned January 3, 2015 | No appointment | No appointment | James Lankford (R) | November 4, 2014 |
| Alabama (Class 2) | Jeff Sessions (R) | Resigned February 8, 2017 | Luther Strange (R) | February 9, 2017 | Doug Jones (D) | December 12, 2017 |
| Minnesota (Class 2) | Al Franken (D) | Resigned January 2, 2018 | Tina Smith (D) | January 3, 2018 | Tina Smith (D) | November 6, 2018 |
| Mississippi (Class 2) | Thad Cochran (R) | Resigned April 1, 2018 | Cindy Hyde-Smith (R) | April 2, 2018 | Cindy Hyde-Smith (R) | November 6, 2018 |
| Arizona (Class 3) | John McCain (R) | Died August 25, 2018 | Jon Kyl (R) | September 4, 2018 – December 31, 2018 (resigned) | Mark Kelly (D) | November 3, 2020 |
| Arizona (Class 3) | John McCain (R) | Died August 25, 2018 | Martha McSally (R) | January 3, 2019 | Mark Kelly (D) | November 3, 2020 |
| Georgia (Class 3) | Johnny Isakson (R) | Resigned December 31, 2019 | Kelly Loeffler (R) | January 6, 2020 | Raphael Warnock (D) | January 5, 2021 |
| California (Class 3) | Kamala Harris (D) | Resigned January 18, 2021 Elected as vice president | Alex Padilla (D) | January 20, 2021 | Alex Padilla (D) | November 8, 2022 |
| Oklahoma (Class 2) | Jim Inhofe (R) | Resigned January 3, 2023 | No appointment | No appointment | Markwayne Mullin (R) | November 8, 2022 |
| Nebraska (Class 2) | Ben Sasse (R) | Resigned January 8, 2023 | Pete Ricketts (R) | January 12, 2023 | Pete Ricketts (R) | November 5, 2024 |
| California (Class 1) | Dianne Feinstein (D) | Died September 29, 2023 | Laphonza Butler (D) | October 1, 2023 | Adam Schiff (D) | November 5, 2024 |
| Ohio (Class 3) | JD Vance (R) | Resigned January 10, 2025 Elected as vice president | Jon Husted (R) | January 21, 2025 | TBD | November 3, 2026 |
| Florida (Class 3) | Marco Rubio (R) | Resigned January 20, 2025 | Ashley Moody (R) | January 21, 2025 | TBD | November 3, 2026 |
| State | Senator | Vacancy event | Senator | Date | Senator | Date |
| State | Original | Original | Appointee | Appointee | Election winner | Election winner |