# List of United States senators from Pennsylvania

Pennsylvania ratified the United States Constitution on December 12, 1787, and elects its U.S. senators to class 1 and class 3. Officeholders are popularly elected, for a six-year term, beginning January 3. Elections are held the first Tuesday after November 1. Before 1914, they were chosen by the Pennsylvania General Assembly; before 1935, their terms began March 4. The state's current U.S. senators are Democrat John Fetterman (since 2023) and Republican Dave McCormick (since 2025), making it one of four states to have a split Senate delegation, along with Maine, Vermont, and Wisconsin. Arlen Specter was Pennsylvania's longest-serving senator (1981–2011).

## List of senators

| Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2006, 2012, 2018, and 2024. The next election will be in 2030. | Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2006, 2012, 2018, and 2024. The next election will be in 2030. | Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2006, 2012, 2018, and 2024. The next election will be in 2030. | Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2006, 2012, 2018, and 2024. The next election will be in 2030. | Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2006, 2012, 2018, and 2024. The next election will be in 2030. | Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2006, 2012, 2018, and 2024. The next election will be in 2030. | C | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. |
| # | Senator | Party | Dates in office | Electoral history | T | C | T | Electoral history | Dates in office | Party | Senator | # |
| 1 | William Maclay | Anti- Admin. | Mar 4, 1789 – Mar 3, 1791 | Elected in 1788.Lost re-election. | 1 | 1st | 1 | Elected in 1788.Retired. | Mar 4, 1789 – Mar 3, 1795 | Pro- Admin. | Robert Morris | 1 |
| Vacant | Vacant | Vacant | Mar 4, 1791 – Dec 1, 1793 | Legislature failed to elect. | 2 | 2nd | 1 | Elected in 1788.Retired. | Mar 4, 1789 – Mar 3, 1795 | Pro- Admin. | Robert Morris | 1 |
| 2 | Albert Gallatin | Anti- Admin. | Dec 2, 1793 – Feb 28, 1794 | Elected to finish the vacant term.Election voided. | 2 | 2nd | 1 | Elected in 1788.Retired. | Mar 4, 1789 – Mar 3, 1795 | Pro- Admin. | Robert Morris | 1 |
| 2 | Albert Gallatin | Anti- Admin. | Dec 2, 1793 – Feb 28, 1794 | Elected to finish the vacant term.Election voided. | 2 | 3rd | 1 | Elected in 1788.Retired. | Mar 4, 1789 – Mar 3, 1795 | Pro- Admin. | Robert Morris | 1 |
| Vacant | Vacant | Vacant | Mar 1, 1794 – Apr 23, 1794 | | 2 | 3rd | 1 | Elected in 1788.Retired. | Mar 4, 1789 – Mar 3, 1795 | Pro- Admin. | Robert Morris | 1 |
| 3 | James Ross | Pro- Admin. | Apr 24, 1794 – Mar 3, 1803 | Elected to finish the vacant term that happened from 1791 to 1793. | 2 | 3rd | 1 | Elected in 1788.Retired. | Mar 4, 1789 – Mar 3, 1795 | Pro- Admin. | Robert Morris | 1 |
| 3 | James Ross | Federalist | Apr 24, 1794 – Mar 3, 1803 | Elected to finish the vacant term that happened from 1791 to 1793. | 2 | 4th | 2 | Elected in 1795.Retired. | Mar 4, 1795 – Mar 3, 1801 | Federalist | William Bingham | 2 |
| 3 | James Ross | Federalist | Apr 24, 1794 – Mar 3, 1803 | Re-elected in 1797.Retired. | 3 | 5th | 2 | Elected in 1795.Retired. | Mar 4, 1795 – Mar 3, 1801 | Federalist | William Bingham | 2 |
| 3 | James Ross | Federalist | Apr 24, 1794 – Mar 3, 1803 | Re-elected in 1797.Retired. | 3 | 6th | 2 | Elected in 1795.Retired. | Mar 4, 1795 – Mar 3, 1801 | Federalist | William Bingham | 2 |
| 3 | James Ross | Federalist | Apr 24, 1794 – Mar 3, 1803 | Re-elected in 1797.Retired. | 3 | 7th | 3 | Elected in 1801.Resigned to become Supervisor of Revenue of Pennsylvania. | Mar 4, 1801 – Jun 30, 1801 | Democratic- Republican | Peter Muhlenberg | 3 |
| 3 | James Ross | Federalist | Apr 24, 1794 – Mar 3, 1803 | Re-elected in 1797.Retired. | 3 | 7th | 3 | | Jun 30, 1801 – Dec 17, 1801 | Vacant | Vacant | Vacant |
| 3 | James Ross | Federalist | Apr 24, 1794 – Mar 3, 1803 | Re-elected in 1797.Retired. | 3 | 7th | 3 | Elected to finish Muhlenberg's term.Retired. | Dec 17, 1801 – Mar 3, 1807 | Democratic- Republican | George Logan | 4 |
| 4 | Samuel Maclay | Democratic- Republican | Mar 4, 1803 – Jan 4, 1809 | Elected in 1802.Resigned. | 4 | 8th | 3 | Elected to finish Muhlenberg's term.Retired. | Dec 17, 1801 – Mar 3, 1807 | Democratic- Republican | George Logan | 4 |
| 4 | Samuel Maclay | Democratic- Republican | Mar 4, 1803 – Jan 4, 1809 | Elected in 1802.Resigned. | 4 | 9th | 3 | Elected to finish Muhlenberg's term.Retired. | Dec 17, 1801 – Mar 3, 1807 | Democratic- Republican | George Logan | 4 |
| 4 | Samuel Maclay | Democratic- Republican | Mar 4, 1803 – Jan 4, 1809 | Elected in 1802.Resigned. | 4 | 10th | 4 | Elected in 1806.Retired. | Mar 4, 1807 – Mar 3, 1813 | Democratic- Republican | Andrew Gregg | 5 |
| Vacant | Vacant | Vacant | Jan 4, 1809 – Jan 9, 1809 | Vacant | 4 | 10th | 4 | Elected in 1806.Retired. | Mar 4, 1807 – Mar 3, 1813 | Democratic- Republican | Andrew Gregg | 5 |
| 5 | Michael Leib | Democratic- Republican | Jan 9, 1809 – Feb 14, 1814 | Elected in 1809 to finish Maclay's term, having been elected to the next term. | 4 | 10th | 4 | Elected in 1806.Retired. | Mar 4, 1807 – Mar 3, 1813 | Democratic- Republican | Andrew Gregg | 5 |
| 5 | Michael Leib | Democratic- Republican | Jan 9, 1809 – Feb 14, 1814 | Elected in 1808.Resigned to become Postmaster of Philadelphia. | 5 | 11th | 4 | Elected in 1806.Retired. | Mar 4, 1807 – Mar 3, 1813 | Democratic- Republican | Andrew Gregg | 5 |
| 5 | Michael Leib | Democratic- Republican | Jan 9, 1809 – Feb 14, 1814 | Elected in 1808.Resigned to become Postmaster of Philadelphia. | 5 | 12th | 4 | Elected in 1806.Retired. | Mar 4, 1807 – Mar 3, 1813 | Democratic- Republican | Andrew Gregg | 5 |
| 5 | Michael Leib | Democratic- Republican | Jan 9, 1809 – Feb 14, 1814 | Elected in 1808.Resigned to become Postmaster of Philadelphia. | 5 | 13th | 5 | Elected in 1812.Retired. | Mar 4, 1813 – Mar 3, 1819 | Democratic- Republican | Abner Lacock | 6 |
| Vacant | Vacant | Vacant | Feb 14, 1814 – Feb 24, 1814 | | 5 | 13th | 5 | Elected in 1812.Retired. | Mar 4, 1813 – Mar 3, 1819 | Democratic- Republican | Abner Lacock | 6 |
| 6 | Jonathan Roberts | Democratic- Republican | Feb 24, 1814 – Mar 3, 1821 | Elected to finish Leib's term. | 5 | 13th | 5 | Elected in 1812.Retired. | Mar 4, 1813 – Mar 3, 1819 | Democratic- Republican | Abner Lacock | 6 |
| 6 | Jonathan Roberts | Democratic- Republican | Feb 24, 1814 – Mar 3, 1821 | Re-elected in late 1814. | 6 | 14th | 5 | Elected in 1812.Retired. | Mar 4, 1813 – Mar 3, 1819 | Democratic- Republican | Abner Lacock | 6 |
| 6 | Jonathan Roberts | Democratic- Republican | Feb 24, 1814 – Mar 3, 1821 | Re-elected in late 1814. | 6 | 15th | 5 | Elected in 1812.Retired. | Mar 4, 1813 – Mar 3, 1819 | Democratic- Republican | Abner Lacock | 6 |
| 6 | Jonathan Roberts | Democratic- Republican | Feb 24, 1814 – Mar 3, 1821 | Re-elected in late 1814. | 6 | 16th | 6 | Elected in 1818.Retired. | Mar 4, 1819 – Mar 3, 1825 | Democratic- Republican | Walter Lowrie | 7 |
| Vacant | Vacant | Vacant | Mar 4, 1821 – Dec 10, 1821 | Legislature failed to elect. | 7 | 17th | 6 | Elected in 1818.Retired. | Mar 4, 1819 – Mar 3, 1825 | Democratic- Republican | Walter Lowrie | 7 |
| 7 | William Findlay | Democratic- Republican | Dec 10, 1821 – Mar 3, 1827 | Elected late in 1821.Retired. | 7 | 17th | 6 | Elected in 1818.Retired. | Mar 4, 1819 – Mar 3, 1825 | Democratic- Republican | Walter Lowrie | 7 |
| 7 | William Findlay | Democratic- Republican | Dec 10, 1821 – Mar 3, 1827 | Elected late in 1821.Retired. | 7 | 18th | 6 | Elected in 1818.Retired. | Mar 4, 1819 – Mar 3, 1825 | Democratic- Republican | Walter Lowrie | 7 |
| 7 | William Findlay | Jacksonian | Dec 10, 1821 – Mar 3, 1827 | Elected late in 1821.Retired. | 7 | 19th | 7 | Elected in 1825.Lost re-election. | Mar 4, 1825 – Mar 3, 1831 | National Republican | William Marks | 8 |
| 8 | Isaac D. Barnard | Jacksonian | Mar 4, 1827 – Dec 6, 1831 | Elected in 1826.Resigned to due ill health. | 8 | 20th | 7 | Elected in 1825.Lost re-election. | Mar 4, 1825 – Mar 3, 1831 | National Republican | William Marks | 8 |
| 8 | Isaac D. Barnard | Jacksonian | Mar 4, 1827 – Dec 6, 1831 | Elected in 1826.Resigned to due ill health. | 8 | 21st | 7 | Elected in 1825.Lost re-election. | Mar 4, 1825 – Mar 3, 1831 | National Republican | William Marks | 8 |
| 8 | Isaac D. Barnard | Jacksonian | Mar 4, 1827 – Dec 6, 1831 | Elected in 1826.Resigned to due ill health. | 8 | 22nd | 8 | Elected in 1830.Resigned to become U.S. Minister to Russia. | Mar 4, 1831 – Jun 30, 1834 | Jacksonian | William Wilkins | 9 |
| Vacant | Vacant | Vacant | Dec 6, 1831 – Dec 13, 1831 | | 8 | 22nd | 8 | Elected in 1830.Resigned to become U.S. Minister to Russia. | Mar 4, 1831 – Jun 30, 1834 | Jacksonian | William Wilkins | 9 |
| 9 | George M. Dallas | Jacksonian | Dec 13, 1831 – Mar 3, 1833 | Elected to finish Barnard's term.Retired. | 8 | 22nd | 8 | Elected in 1830.Resigned to become U.S. Minister to Russia. | Mar 4, 1831 – Jun 30, 1834 | Jacksonian | William Wilkins | 9 |
| Vacant | Vacant | Vacant | Mar 4, 1833 – Dec 7, 1833 | Legislature failed to elect. | 9 | 23rd | 8 | Elected in 1830.Resigned to become U.S. Minister to Russia. | Mar 4, 1831 – Jun 30, 1834 | Jacksonian | William Wilkins | 9 |
| 10 | Samuel McKean | Jacksonian | Dec 7, 1833 – Mar 3, 1839 | Elected late in 1833. | 9 | 23rd | 8 | Elected in 1830.Resigned to become U.S. Minister to Russia. | Mar 4, 1831 – Jun 30, 1834 | Jacksonian | William Wilkins | 9 |
| 10 | Samuel McKean | Jacksonian | Dec 7, 1833 – Mar 3, 1839 | Elected late in 1833. | 9 | 23rd | 8 | | Jun 30, 1834 – Dec 6, 1834 | Vacant | Vacant | Vacant |
| 10 | Samuel McKean | Jacksonian | Dec 7, 1833 – Mar 3, 1839 | Elected late in 1833. | 9 | 23rd | 8 | Elected to finish Wilkins's term. | Dec 6, 1834 – Mar 5, 1845 | Jacksonian | James Buchanan | 10 |
| 10 | Samuel McKean | Jacksonian | Dec 7, 1833 – Mar 3, 1839 | Elected late in 1833. | 9 | 24th | 8 | Elected to finish Wilkins's term. | Dec 6, 1834 – Mar 5, 1845 | Jacksonian | James Buchanan | 10 |
| 10 | Samuel McKean | Democratic | Dec 7, 1833 – Mar 3, 1839 | Elected late in 1833. | 9 | 25th | 9 | Re-elected in 1836. | Dec 6, 1834 – Mar 5, 1845 | Democratic | James Buchanan | 10 |
| Vacant | Vacant | Vacant | Mar 4, 1839 – Jan 14, 1840 | Legislature failed to elect. | 10 | 26th | 9 | Re-elected in 1836. | Dec 6, 1834 – Mar 5, 1845 | Democratic | James Buchanan | 10 |
| 11 | Daniel Sturgeon | Democratic | Jan 14, 1840 – Mar 3, 1851 | Elected late in 1840. | 10 | 26th | 9 | Re-elected in 1836. | Dec 6, 1834 – Mar 5, 1845 | Democratic | James Buchanan | 10 |
| 11 | Daniel Sturgeon | Democratic | Jan 14, 1840 – Mar 3, 1851 | Elected late in 1840. | 10 | 27th | 9 | Re-elected in 1836. | Dec 6, 1834 – Mar 5, 1845 | Democratic | James Buchanan | 10 |
| 11 | Daniel Sturgeon | Democratic | Jan 14, 1840 – Mar 3, 1851 | Elected late in 1840. | 10 | 28th | 10 | Re-elected in 1843.Resigned to become U.S. Secretary of State. | Dec 6, 1834 – Mar 5, 1845 | Democratic | James Buchanan | 10 |
| 11 | Daniel Sturgeon | Democratic | Jan 14, 1840 – Mar 3, 1851 | Re-elected in 1845.Retired. | 11 | 29th | 10 | Re-elected in 1843.Resigned to become U.S. Secretary of State. | Dec 6, 1834 – Mar 5, 1845 | Democratic | James Buchanan | 10 |
| 11 | Daniel Sturgeon | Democratic | Jan 14, 1840 – Mar 3, 1851 | Re-elected in 1845.Retired. | 11 | 29th | 10 | | Mar 5, 1845 – Mar 13, 1845 | Vacant | Vacant | Vacant |
| 11 | Daniel Sturgeon | Democratic | Jan 14, 1840 – Mar 3, 1851 | Re-elected in 1845.Retired. | 11 | 29th | 10 | Elected in 1845 to finish Buchanan's term.Retired. | Mar 13, 1845 – Mar 3, 1849 | Democratic | Simon Cameron | 11 |
| 11 | Daniel Sturgeon | Democratic | Jan 14, 1840 – Mar 3, 1851 | Re-elected in 1845.Retired. | 11 | 30th | 10 | Elected in 1845 to finish Buchanan's term.Retired. | Mar 13, 1845 – Mar 3, 1849 | Democratic | Simon Cameron | 11 |
| 11 | Daniel Sturgeon | Democratic | Jan 14, 1840 – Mar 3, 1851 | Re-elected in 1845.Retired. | 11 | 31st | 11 | Elected in 1849. | Mar 4, 1849 – Mar 3, 1855 | Whig | James Cooper | 12 |
| 12 | Richard Brodhead | Democratic | Mar 4, 1851 – Mar 3, 1857 | Elected in 1851. | 12 | 32nd | 11 | Elected in 1849. | Mar 4, 1849 – Mar 3, 1855 | Whig | James Cooper | 12 |
| 12 | Richard Brodhead | Democratic | Mar 4, 1851 – Mar 3, 1857 | Elected in 1851. | 12 | 33rd | 11 | Elected in 1849. | Mar 4, 1849 – Mar 3, 1855 | Whig | James Cooper | 12 |
| 12 | Richard Brodhead | Democratic | Mar 4, 1851 – Mar 3, 1857 | Elected in 1851. | 12 | 34th | 12 | Legislature failed to elect. | Mar 4, 1855 – Jan 14, 1856 | Vacant | Vacant | Vacant |
| 12 | Richard Brodhead | Democratic | Mar 4, 1851 – Mar 3, 1857 | Elected in 1851. | 12 | 34th | 12 | Elected late in 1856.Retired. | Jan 14, 1856 – Mar 3, 1861 | Democratic | William Bigler | 13 |
| 13 | Simon Cameron | Republican | Mar 4, 1857 – Mar 4, 1861 | Elected in 1857.Resigned to become U.S. Secretary of War. | 13 | 35th | 12 | Elected late in 1856.Retired. | Jan 14, 1856 – Mar 3, 1861 | Democratic | William Bigler | 13 |
| 13 | Simon Cameron | Republican | Mar 4, 1857 – Mar 4, 1861 | Elected in 1857.Resigned to become U.S. Secretary of War. | 13 | 36th | 12 | Elected late in 1856.Retired. | Jan 14, 1856 – Mar 3, 1861 | Democratic | William Bigler | 13 |
| Vacant | Vacant | Vacant | Mar 4, 1861 – Mar 14, 1861 | | 13 | 37th | 13 | Elected in 1861.Lost re-election. | Mar 4, 1861 – Mar 3, 1867 | Republican | Edgar Cowan | 14 |
| 14 | David Wilmot | Republican | Mar 14, 1861 – Mar 3, 1863 | Elected in 1861 to finish Cameron's term.Retired. | 13 | 37th | 13 | Elected in 1861.Lost re-election. | Mar 4, 1861 – Mar 3, 1867 | Republican | Edgar Cowan | 14 |
| 15 | Charles R. Buckalew | Democratic | Mar 4, 1863 – Mar 3, 1869 | Elected in 1863. | 14 | 38th | 13 | Elected in 1861.Lost re-election. | Mar 4, 1861 – Mar 3, 1867 | Republican | Edgar Cowan | 14 |
| 15 | Charles R. Buckalew | Democratic | Mar 4, 1863 – Mar 3, 1869 | Elected in 1863. | 14 | 39th | 13 | Elected in 1861.Lost re-election. | Mar 4, 1861 – Mar 3, 1867 | Republican | Edgar Cowan | 14 |
| 15 | Charles R. Buckalew | Democratic | Mar 4, 1863 – Mar 3, 1869 | Elected in 1863. | 14 | 40th | 14 | Elected in 1867. | Mar 4, 1867 – Mar 12, 1877 | Republican | Simon Cameron | 15 |
| 16 | John Scott | Republican | Mar 4, 1869 – Mar 3, 1875 | Elected in 1869.Retired. | 15 | 41st | 14 | Elected in 1867. | Mar 4, 1867 – Mar 12, 1877 | Republican | Simon Cameron | 15 |
| 16 | John Scott | Republican | Mar 4, 1869 – Mar 3, 1875 | Elected in 1869.Retired. | 15 | 42nd | 14 | Elected in 1867. | Mar 4, 1867 – Mar 12, 1877 | Republican | Simon Cameron | 15 |
| 16 | John Scott | Republican | Mar 4, 1869 – Mar 3, 1875 | Elected in 1869.Retired. | 15 | 43rd | 15 | Re-elected in 1873.Resigned. | Mar 4, 1867 – Mar 12, 1877 | Republican | Simon Cameron | 15 |
| 17 | William A. Wallace | Democratic | Mar 4, 1875 – Mar 3, 1881 | Elected in 1875.Lost re-election. | 16 | 44th | 15 | Re-elected in 1873.Resigned. | Mar 4, 1867 – Mar 12, 1877 | Republican | Simon Cameron | 15 |
| 17 | William A. Wallace | Democratic | Mar 4, 1875 – Mar 3, 1881 | Elected in 1875.Lost re-election. | 16 | 45th | 15 | Re-elected in 1873.Resigned. | Mar 4, 1867 – Mar 12, 1877 | Republican | Simon Cameron | 15 |
| 17 | William A. Wallace | Democratic | Mar 4, 1875 – Mar 3, 1881 | Elected in 1875.Lost re-election. | 16 | 45th | 15 | | Mar 12, 1877 – Mar 20, 1877 | Vacant | Vacant | Vacant |
| 17 | William A. Wallace | Democratic | Mar 4, 1875 – Mar 3, 1881 | Elected in 1875.Lost re-election. | 16 | 45th | 15 | Elected in 1877 to finish his father's term. | Mar 20, 1877 – Mar 3, 1897 | Republican | J. Donald Cameron | 16 |
| 17 | William A. Wallace | Democratic | Mar 4, 1875 – Mar 3, 1881 | Elected in 1875.Lost re-election. | 16 | 46th | 16 | Re-elected in 1879. | Mar 20, 1877 – Mar 3, 1897 | Republican | J. Donald Cameron | 16 |
| 18 | John I. Mitchell | Republican | Mar 4, 1881 – Mar 3, 1887 | Elected in 1881. | 17 | 47th | 16 | Re-elected in 1879. | Mar 20, 1877 – Mar 3, 1897 | Republican | J. Donald Cameron | 16 |
| 18 | John I. Mitchell | Republican | Mar 4, 1881 – Mar 3, 1887 | Elected in 1881. | 17 | 48th | 16 | Re-elected in 1879. | Mar 20, 1877 – Mar 3, 1897 | Republican | J. Donald Cameron | 16 |
| 18 | John I. Mitchell | Republican | Mar 4, 1881 – Mar 3, 1887 | Elected in 1881. | 17 | 49th | 17 | Re-elected in 1885. | Mar 20, 1877 – Mar 3, 1897 | Republican | J. Donald Cameron | 16 |
| 19 | Matthew Quay | Republican | Mar 4, 1887 – Mar 3, 1899 | Elected in early 1887. | 18 | 50th | 17 | Re-elected in 1885. | Mar 20, 1877 – Mar 3, 1897 | Republican | J. Donald Cameron | 16 |
| 19 | Matthew Quay | Republican | Mar 4, 1887 – Mar 3, 1899 | Elected in early 1887. | 18 | 51st | 17 | Re-elected in 1885. | Mar 20, 1877 – Mar 3, 1897 | Republican | J. Donald Cameron | 16 |
| 19 | Matthew Quay | Republican | Mar 4, 1887 – Mar 3, 1899 | Elected in early 1887. | 18 | 52nd | 18 | Re-elected in 1891.Retired. | Mar 20, 1877 – Mar 3, 1897 | Republican | J. Donald Cameron | 16 |
| 19 | Matthew Quay | Republican | Mar 4, 1887 – Mar 3, 1899 | Re-elected in 1893.Legislature failed to re-elect. | 19 | 53rd | 18 | Re-elected in 1891.Retired. | Mar 20, 1877 – Mar 3, 1897 | Republican | J. Donald Cameron | 16 |
| 19 | Matthew Quay | Republican | Mar 4, 1887 – Mar 3, 1899 | Re-elected in 1893.Legislature failed to re-elect. | 19 | 54th | 18 | Re-elected in 1891.Retired. | Mar 20, 1877 – Mar 3, 1897 | Republican | J. Donald Cameron | 16 |
| 19 | Matthew Quay | Republican | Mar 4, 1887 – Mar 3, 1899 | Re-elected in 1893.Legislature failed to re-elect. | 19 | 55th | 19 | Elected in 1897. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 19 | Vacant | Vacant | Mar 4, 1899 – Jan 16, 1901 | Quay was appointed to continue the term, but the Senate rejected his appointment. | 20 | 56th | 19 | Elected in 1897. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 19 | Matthew Quay | Republican | Jan 16, 1901 – May 28, 1904 | Elected late in 1901.Died. | 20 | 56th | 19 | Elected in 1897. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 19 | Matthew Quay | Republican | Jan 16, 1901 – May 28, 1904 | Elected late in 1901.Died. | 20 | 57th | 19 | Elected in 1897. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 19 | Matthew Quay | Republican | Jan 16, 1901 – May 28, 1904 | Elected late in 1901.Died. | 20 | 58th | 20 | Re-elected in 1903. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 20 | Philander C. Knox | Republican | Jun 10, 1904 – Mar 3, 1909 | Appointed to continue Quay's term.Elected in 1905 to finish Quay's term. | 20 | 58th | 20 | Re-elected in 1903. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 20 | Philander C. Knox | Republican | Jun 10, 1904 – Mar 3, 1909 | Re-elected in 1905.Resigned to become U.S. Secretary of State. | 21 | 59th | 20 | Re-elected in 1903. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 20 | Philander C. Knox | Republican | Jun 10, 1904 – Mar 3, 1909 | Re-elected in 1905.Resigned to become U.S. Secretary of State. | 21 | 60th | 20 | Re-elected in 1903. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| Vacant | Vacant | Vacant | Mar 4, 1909 – Mar 17, 1909 | | 21 | 61st | 21 | Re-elected in 1909. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 21 | George T. Oliver | Republican | Mar 17, 1909 – Mar 3, 1917 | Elected to finish Knox's term | 21 | 61st | 21 | Re-elected in 1909. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 21 | George T. Oliver | Republican | Mar 17, 1909 – Mar 3, 1917 | Re-elected in 1911.Retired. | 22 | 62nd | 21 | Re-elected in 1909. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 21 | George T. Oliver | Republican | Mar 17, 1909 – Mar 3, 1917 | Re-elected in 1911.Retired. | 22 | 63rd | 21 | Re-elected in 1909. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 21 | George T. Oliver | Republican | Mar 17, 1909 – Mar 3, 1917 | Re-elected in 1911.Retired. | 22 | 64th | 22 | Re-elected in 1914. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 22 | Philander C. Knox | Republican | Mar 4, 1917 – Oct 12, 1921 | Elected in 1916.Died. | 23 | 65th | 22 | Re-elected in 1914. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 22 | Philander C. Knox | Republican | Mar 4, 1917 – Oct 12, 1921 | Elected in 1916.Died. | 23 | 66th | 22 | Re-elected in 1914. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 22 | Philander C. Knox | Republican | Mar 4, 1917 – Oct 12, 1921 | Elected in 1916.Died. | 23 | 67th | 23 | Re-elected in 1920.Died. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| Vacant | Vacant | Vacant | Oct 12, 1921 – Oct 24, 1921 | | 23 | 67th | 23 | Re-elected in 1920.Died. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 23 | William E. Crow | Republican | Oct 24, 1921 – Aug 2, 1922 | Appointed to continue Knox's term.Died. | 23 | 67th | 23 | Re-elected in 1920.Died. | Mar 4, 1897 – Dec 31, 1921 | Republican | Boies Penrose | 17 |
| 23 | William E. Crow | Republican | Oct 24, 1921 – Aug 2, 1922 | Appointed to continue Knox's term.Died. | 23 | 67th | 23 | | Dec 31, 1921 – Jan 9, 1922 | Vacant | Vacant | Vacant |
| 23 | William E. Crow | Republican | Oct 24, 1921 – Aug 2, 1922 | Appointed to continue Knox's term.Died. | 23 | 67th | 23 | Appointed to continue Penrose's term.Elected to finish Penrose's term.Lost renomination. | Jan 9, 1922 – Mar 3, 1927 | Republican | George W. Pepper | 18 |
| Vacant | Vacant | Vacant | Aug 2, 1922 – Aug 8, 1922 | | 23 | 67th | 23 | Appointed to continue Penrose's term.Elected to finish Penrose's term.Lost renomination. | Jan 9, 1922 – Mar 3, 1927 | Republican | George W. Pepper | 18 |
| 24 | David A. Reed | Republican | Aug 8, 1922 – Jan 3, 1935 | Appointed to continue Knox's term.Elected to finish Knox's term. | 23 | 67th | 23 | Appointed to continue Penrose's term.Elected to finish Penrose's term.Lost renomination. | Jan 9, 1922 – Mar 3, 1927 | Republican | George W. Pepper | 18 |
| 24 | David A. Reed | Republican | Aug 8, 1922 – Jan 3, 1935 | Elected in 1922. | 24 | 68th | 23 | Appointed to continue Penrose's term.Elected to finish Penrose's term.Lost renomination. | Jan 9, 1922 – Mar 3, 1927 | Republican | George W. Pepper | 18 |
| 24 | David A. Reed | Republican | Aug 8, 1922 – Jan 3, 1935 | Elected in 1922. | 24 | 69th | 23 | Appointed to continue Penrose's term.Elected to finish Penrose's term.Lost renomination. | Jan 9, 1922 – Mar 3, 1927 | Republican | George W. Pepper | 18 |
| 24 | David A. Reed | Republican | Aug 8, 1922 – Jan 3, 1935 | Elected in 1922. | 24 | 70th | 24 | William Scott Vare (R) was elected in 1926, but the Governor refused to certify the election and the Senate refused to qualify him. | Mar 4, 1927 – Dec 9, 1929 | Vacant | Vacant | Vacant |
| 24 | David A. Reed | Republican | Aug 8, 1922 – Jan 3, 1935 | Re-elected in 1928.Lost re-election. | 25 | 71st | 24 | William Scott Vare (R) was elected in 1926, but the Governor refused to certify the election and the Senate refused to qualify him. | Mar 4, 1927 – Dec 9, 1929 | Vacant | Vacant | Vacant |
| 24 | David A. Reed | Republican | Aug 8, 1922 – Jan 3, 1935 | Re-elected in 1928.Lost re-election. | 25 | 71st | 24 | Appointed to continue Vare's term.Lost nomination to finish Vare's term. | Dec 11, 1929 – Dec 1, 1930 | Republican | Joseph R. Grundy | 19 |
| 24 | David A. Reed | Republican | Aug 8, 1922 – Jan 3, 1935 | Re-elected in 1928.Lost re-election. | 25 | 71st | 24 | Elected in 1930 to finish Vare's term | Dec 2, 1930 – Jan 3, 1945 | Republican | James J. Davis | 20 |
| 24 | David A. Reed | Republican | Aug 8, 1922 – Jan 3, 1935 | Re-elected in 1928.Lost re-election. | 25 | 72nd | 24 | Elected in 1930 to finish Vare's term | Dec 2, 1930 – Jan 3, 1945 | Republican | James J. Davis | 20 |
| 24 | David A. Reed | Republican | Aug 8, 1922 – Jan 3, 1935 | Re-elected in 1928.Lost re-election. | 25 | 73rd | 25 | Re-elected in 1932. | Dec 2, 1930 – Jan 3, 1945 | Republican | James J. Davis | 20 |
| 25 | Joe Guffey | Democratic | Jan 3, 1935 – Jan 3, 1947 | Elected in 1934. | 26 | 74th | 25 | Re-elected in 1932. | Dec 2, 1930 – Jan 3, 1945 | Republican | James J. Davis | 20 |
| 25 | Joe Guffey | Democratic | Jan 3, 1935 – Jan 3, 1947 | Elected in 1934. | 26 | 75th | 25 | Re-elected in 1932. | Dec 2, 1930 – Jan 3, 1945 | Republican | James J. Davis | 20 |
| 25 | Joe Guffey | Democratic | Jan 3, 1935 – Jan 3, 1947 | Elected in 1934. | 26 | 76th | 26 | Re-elected in 1938.Lost re-election. | Dec 2, 1930 – Jan 3, 1945 | Republican | James J. Davis | 20 |
| 25 | Joe Guffey | Democratic | Jan 3, 1935 – Jan 3, 1947 | Re-elected in 1940.Lost re-election. | 27 | 77th | 26 | Re-elected in 1938.Lost re-election. | Dec 2, 1930 – Jan 3, 1945 | Republican | James J. Davis | 20 |
| 25 | Joe Guffey | Democratic | Jan 3, 1935 – Jan 3, 1947 | Re-elected in 1940.Lost re-election. | 27 | 78th | 26 | Re-elected in 1938.Lost re-election. | Dec 2, 1930 – Jan 3, 1945 | Republican | James J. Davis | 20 |
| 25 | Joe Guffey | Democratic | Jan 3, 1935 – Jan 3, 1947 | Re-elected in 1940.Lost re-election. | 27 | 79th | 27 | Elected in 1944.Lost re-election. | Jan 3, 1945 – Jan 3, 1951 | Democratic | Francis Myers | 21 |
| 26 | Edward Martin | Republican | Jan 3, 1947 – Jan 3, 1959 | Elected in 1946. | 28 | 80th | 27 | Elected in 1944.Lost re-election. | Jan 3, 1945 – Jan 3, 1951 | Democratic | Francis Myers | 21 |
| 26 | Edward Martin | Republican | Jan 3, 1947 – Jan 3, 1959 | Elected in 1946. | 28 | 81st | 27 | Elected in 1944.Lost re-election. | Jan 3, 1945 – Jan 3, 1951 | Democratic | Francis Myers | 21 |
| 26 | Edward Martin | Republican | Jan 3, 1947 – Jan 3, 1959 | Elected in 1946. | 28 | 82nd | 28 | Elected in 1950.Lost re-election. | Jan 3, 1951 – Jan 3, 1957 | Republican | James H. Duff | 22 |
| 26 | Edward Martin | Republican | Jan 3, 1947 – Jan 3, 1959 | Re-elected in 1952.Retired. | 29 | 83rd | 28 | Elected in 1950.Lost re-election. | Jan 3, 1951 – Jan 3, 1957 | Republican | James H. Duff | 22 |
| 26 | Edward Martin | Republican | Jan 3, 1947 – Jan 3, 1959 | Re-elected in 1952.Retired. | 29 | 84th | 28 | Elected in 1950.Lost re-election. | Jan 3, 1951 – Jan 3, 1957 | Republican | James H. Duff | 22 |
| 26 | Edward Martin | Republican | Jan 3, 1947 – Jan 3, 1959 | Re-elected in 1952.Retired. | 29 | 85th | 29 | Elected in 1956. | Jan 3, 1957 – Jan 3, 1969 | Democratic | Joseph S. Clark Jr. | 23 |
| 27 | Hugh Scott | Republican | Jan 3, 1959 – Jan 3, 1977 | Elected in 1958. | 30 | 86th | 29 | Elected in 1956. | Jan 3, 1957 – Jan 3, 1969 | Democratic | Joseph S. Clark Jr. | 23 |
| 27 | Hugh Scott | Republican | Jan 3, 1959 – Jan 3, 1977 | Elected in 1958. | 30 | 87th | 29 | Elected in 1956. | Jan 3, 1957 – Jan 3, 1969 | Democratic | Joseph S. Clark Jr. | 23 |
| 27 | Hugh Scott | Republican | Jan 3, 1959 – Jan 3, 1977 | Elected in 1958. | 30 | 88th | 30 | Re-elected in 1962.Lost re-election. | Jan 3, 1957 – Jan 3, 1969 | Democratic | Joseph S. Clark Jr. | 23 |
| 27 | Hugh Scott | Republican | Jan 3, 1959 – Jan 3, 1977 | Re-elected in 1964. | 31 | 89th | 30 | Re-elected in 1962.Lost re-election. | Jan 3, 1957 – Jan 3, 1969 | Democratic | Joseph S. Clark Jr. | 23 |
| 27 | Hugh Scott | Republican | Jan 3, 1959 – Jan 3, 1977 | Re-elected in 1964. | 31 | 90th | 30 | Re-elected in 1962.Lost re-election. | Jan 3, 1957 – Jan 3, 1969 | Democratic | Joseph S. Clark Jr. | 23 |
| 27 | Hugh Scott | Republican | Jan 3, 1959 – Jan 3, 1977 | Re-elected in 1964. | 31 | 91st | 31 | Elected in 1968. | Jan 3, 1969 – Jan 3, 1981 | Republican | Richard Schweiker | 24 |
| 27 | Hugh Scott | Republican | Jan 3, 1959 – Jan 3, 1977 | Re-elected in 1970.Retired. | 32 | 92nd | 31 | Elected in 1968. | Jan 3, 1969 – Jan 3, 1981 | Republican | Richard Schweiker | 24 |
| 27 | Hugh Scott | Republican | Jan 3, 1959 – Jan 3, 1977 | Re-elected in 1970.Retired. | 32 | 93rd | 31 | Elected in 1968. | Jan 3, 1969 – Jan 3, 1981 | Republican | Richard Schweiker | 24 |
| 27 | Hugh Scott | Republican | Jan 3, 1959 – Jan 3, 1977 | Re-elected in 1970.Retired. | 32 | 94th | 32 | Re-elected in 1974.Retired. | Jan 3, 1969 – Jan 3, 1981 | Republican | Richard Schweiker | 24 |
| 28 | John Heinz | Republican | Jan 3, 1977 – Apr 4, 1991 | Elected in 1976. | 33 | 95th | 32 | Re-elected in 1974.Retired. | Jan 3, 1969 – Jan 3, 1981 | Republican | Richard Schweiker | 24 |
| 28 | John Heinz | Republican | Jan 3, 1977 – Apr 4, 1991 | Elected in 1976. | 33 | 96th | 32 | Re-elected in 1974.Retired. | Jan 3, 1969 – Jan 3, 1981 | Republican | Richard Schweiker | 24 |
| 28 | John Heinz | Republican | Jan 3, 1977 – Apr 4, 1991 | Elected in 1976. | 33 | 97th | 33 | Elected in 1980. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 28 | John Heinz | Republican | Jan 3, 1977 – Apr 4, 1991 | Re-elected in 1982. | 34 | 98th | 33 | Elected in 1980. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 28 | John Heinz | Republican | Jan 3, 1977 – Apr 4, 1991 | Re-elected in 1982. | 34 | 99th | 33 | Elected in 1980. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 28 | John Heinz | Republican | Jan 3, 1977 – Apr 4, 1991 | Re-elected in 1982. | 34 | 100th | 34 | Re-elected in 1986. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 28 | John Heinz | Republican | Jan 3, 1977 – Apr 4, 1991 | Re-elected in 1988.Died. | 35 | 101st | 34 | Re-elected in 1986. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 28 | John Heinz | Republican | Jan 3, 1977 – Apr 4, 1991 | Re-elected in 1988.Died. | 35 | 102nd | 34 | Re-elected in 1986. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| Vacant | Vacant | Vacant | Apr 4, 1991 – May 9, 1991 | | 35 | 102nd | 34 | Re-elected in 1986. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 29 | Harris Wofford | Democratic | May 9, 1991 – Jan 3, 1995 | Appointed to continue Heinz's term.Elected to finish Heinz's term.Lost re-election. | 35 | 102nd | 34 | Re-elected in 1986. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 29 | Harris Wofford | Democratic | May 9, 1991 – Jan 3, 1995 | Appointed to continue Heinz's term.Elected to finish Heinz's term.Lost re-election. | 35 | 103rd | 35 | Re-elected in 1992. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 30 | Rick Santorum | Republican | Jan 3, 1995 – Jan 3, 2007 | Elected in 1994. | 36 | 104th | 35 | Re-elected in 1992. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 30 | Rick Santorum | Republican | Jan 3, 1995 – Jan 3, 2007 | Elected in 1994. | 36 | 105th | 35 | Re-elected in 1992. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 30 | Rick Santorum | Republican | Jan 3, 1995 – Jan 3, 2007 | Elected in 1994. | 36 | 106th | 36 | Re-elected in 1998. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 30 | Rick Santorum | Republican | Jan 3, 1995 – Jan 3, 2007 | Re-elected in 2000.Lost re-election. | 37 | 107th | 36 | Re-elected in 1998. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 30 | Rick Santorum | Republican | Jan 3, 1995 – Jan 3, 2007 | Re-elected in 2000.Lost re-election. | 37 | 108th | 36 | Re-elected in 1998. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 30 | Rick Santorum | Republican | Jan 3, 1995 – Jan 3, 2007 | Re-elected in 2000.Lost re-election. | 37 | 109th | 37 | Re-elected in 2004.Changed party on Apr 28, 2009.Lost renomination. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 31 | Bob Casey Jr. | Democratic | Jan 3, 2007 – Jan 3, 2025 | Elected in 2006. | 38 | 110th | 37 | Re-elected in 2004.Changed party on Apr 28, 2009.Lost renomination. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 31 | Bob Casey Jr. | Democratic | Jan 3, 2007 – Jan 3, 2025 | Elected in 2006. | 38 | 111th | 37 | Re-elected in 2004.Changed party on Apr 28, 2009.Lost renomination. | Jan 3, 1981 – Jan 3, 2011 | Republican | Arlen Specter | 25 |
| 31 | Bob Casey Jr. | Democratic | Jan 3, 2007 – Jan 3, 2025 | Elected in 2006. | 38 | 111th | 37 | Re-elected in 2004.Changed party on Apr 28, 2009.Lost renomination. | Jan 3, 1981 – Jan 3, 2011 | Democratic | Arlen Specter | 25 |
| 31 | Bob Casey Jr. | Democratic | Jan 3, 2007 – Jan 3, 2025 | Elected in 2006. | 38 | 112th | 38 | Elected in 2010. | Jan 3, 2011 – Jan 3, 2023 | Republican | Pat Toomey | 26 |
| 31 | Bob Casey Jr. | Democratic | Jan 3, 2007 – Jan 3, 2025 | Re-elected in 2012. | 39 | 113th | 38 | Elected in 2010. | Jan 3, 2011 – Jan 3, 2023 | Republican | Pat Toomey | 26 |
| 31 | Bob Casey Jr. | Democratic | Jan 3, 2007 – Jan 3, 2025 | Re-elected in 2012. | 39 | 114th | 38 | Elected in 2010. | Jan 3, 2011 – Jan 3, 2023 | Republican | Pat Toomey | 26 |
| 31 | Bob Casey Jr. | Democratic | Jan 3, 2007 – Jan 3, 2025 | Re-elected in 2012. | 39 | 115th | 39 | Re-elected in 2016.Retired. | Jan 3, 2011 – Jan 3, 2023 | Republican | Pat Toomey | 26 |
| 31 | Bob Casey Jr. | Democratic | Jan 3, 2007 – Jan 3, 2025 | Re-elected in 2018.Lost re-election. | 40 | 116th | 39 | Re-elected in 2016.Retired. | Jan 3, 2011 – Jan 3, 2023 | Republican | Pat Toomey | 26 |
| 31 | Bob Casey Jr. | Democratic | Jan 3, 2007 – Jan 3, 2025 | Re-elected in 2018.Lost re-election. | 40 | 117th | 39 | Re-elected in 2016.Retired. | Jan 3, 2011 – Jan 3, 2023 | Republican | Pat Toomey | 26 |
| 31 | Bob Casey Jr. | Democratic | Jan 3, 2007 – Jan 3, 2025 | Re-elected in 2018.Lost re-election. | 40 | 118th | 40 | Elected in 2022. | Jan 3, 2023 – present | Democratic | John Fetterman | 27 |
| 32 | Dave McCormick | Republican | Jan 3, 2025 – present | Elected in 2024. | 41 | 119th | 40 | Elected in 2022. | Jan 3, 2023 – present | Democratic | John Fetterman | 27 |
| 32 | Dave McCormick | Republican | Jan 3, 2025 – present | Elected in 2024. | 41 | 120th | 40 | Elected in 2022. | Jan 3, 2023 – present | Democratic | John Fetterman | 27 |
| 32 | Dave McCormick | Republican | Jan 3, 2025 – present | Elected in 2024. | 41 | 121st | 41 | To be determined in the 2028 election. | To be determined in the 2028 election. | To be determined in the 2028 election. | To be determined in the 2028 election. | To be determined in the 2028 election. |
| To be determined in the 2030 election. | To be determined in the 2030 election. | To be determined in the 2030 election. | To be determined in the 2030 election. | To be determined in the 2030 election. | 42 | 122nd | 41 | To be determined in the 2028 election. | To be determined in the 2028 election. | To be determined in the 2028 election. | To be determined in the 2028 election. | To be determined in the 2028 election. |
| # | Senator | Party | Years in office | Electoral history | T | C | T | Electoral history | Years in office | Party | Senator | # |
| Class 1 | Class 1 | Class 1 | Class 1 | Class 1 | Class 1 | C | Class 3 | Class 3 | Class 3 | Class 3 | Class 3 | Class 3 |