A
| Representative | Party | District | Years | District home | Note |
|---|---|---|---|---|---|
| Ernest F. Acheson | Republican | 24th | March 4, 1895 – March 4, 1909 | ||
| Ephraim L. Acker | Democratic | 6th | March 4, 1871 – March 4, 1873 | ||
| Robert Adams, Jr. | Republican | 2nd | December 19, 1893 – June 1, 1906 | Philadelphia | Died |
| William Addams | Jacksonian | 7th | March 4, 1825 – March 4, 1829 | ||
| John A. Ahl | Democratic | 16th | March 4, 1857 – March 4, 1859 | ||
| William D.B. Ainey | Republican | 14th | November 7, 1911 – March 4, 1915 | ||
| Charles Albright | Republican | At-large | March 4, 1873 – March 4, 1875 | ||
| Robert G. Allen | Democratic | 28th | January 3, 1937 – January 3, 1941 | ||
| James Allison, Jr. | Jacksonian Democratic-Republican | 16th | March 4, 1823 – ????, 1825 | ||
| John Allison | Whig | 20th | March 4, 1851 – March 4, 1853 | ||
| Opposition | 23rd | March 4, 1855 – March 4, 1857 | |||
| Robert Allison | Anti-Masonic | 12th | March 4, 1831 – March 4, 1833 | Huntingdon | |
| Jason Altmire | Democratic | 4th | January 3, 2007 – present | McCandless | Incumbent |
| Lemuel Amerman | Democratic | 11th | March 4, 1891 – March 4, 1893 | Scranton | |
| Joseph S. Ammerman | Democratic | 23rd | January 3, 1977 – January 3, 1979 | ||
| Sydenham E. Ancona | Democratic | 8th | March 4, 1861 – March 4, 1867 | ||
| Isaac Anderson | Democratic-Republican | 3rd | March 4, 1803 – March 4, 1807 | ||
| Samuel Anderson | Adams | 4th | March 4, 1827 – March 4, 1829 | ||
| William Anderson | Democratic-Republican | 1st | March 4, 1809 – March 4, 1815 | Philadelphia | |
| March 4, 1817 – March 4, 1819 | |||||
| Joseph B. Anthony | Jacksonian | 16th | March 4, 1833 – March 4, 1837 | ||
| James Armstrong | Pro-Administration | At-large | March 4, 1793 – March 4, 1795 | ||
| William H. Armstrong | Republican | 18th | March 4, 1869 – March 4, 1871 | ||
| William C. Arnold | Republican | 28th | March 4, 1895 – March 4, 1899 | ||
| Michael W. Ash | Jacksonian | 3rd | March 4, 1835 – March 4, 1837 | ||
| Eugene Atkinson | Democratic | 25th | January 3, 1979 – October 14, 1981 | ||
| Republican | October 14, 1981 – January 3, 1983 | ||||
| Louis E. Atkinson | Republican | 18th | March 4, 1883 – March 4, 1893 |
Read more about this topic: List Of United States Representatives From Pennsylvania