When Maine became a state in 1820, it had seven Congressional districts credited to it. Prior to that it was part of Massachusetts, which had 20 districts after the 1810 census. Since Maine became a state, all but two districts have been reallocated.
| Representative | Party | Years ↑ | District home | Note |
| Ezekiel Whitman | Federalist | March 4, 1821 – June 1, 1822 | | Redistricted from the Massachusetts 15th district, resigned |
| Vacant | June 1, 1822 – December 2, 1822 |
| Mark Harris | Democratic-Republican | December 2, 1822 – March 3, 1823 | | |
| Stephen Longfellow | Adams-Clay Federalist | March 4, 1823 – March 3, 1825 | | |
| John Anderson | Jacksonian | March 4, 1825 – March 3, 1833 | | retired to run for Mayor of Portland |
| Francis Smith | Jacksonian | March 4, 1833 – March 3, 1837 | | |
| Democratic | March 4, 1837 – March 3, 1839 | |
| Albert Smith | Democratic | March 4, 1839 – March 3, 1841 | | |
| William Pitt Fessenden | Whig | March 4, 1841 – March 3, 1843 | | |
| Robert P. Dunlap | Democratic | March 4, 1843 – March 3, 1847 | | |
| Asa Clapp | Democratic | March 4, 1847 – March 3, 1849 | | |
| Nathaniel Littlefield | Democratic | March 4, 1849 – March 3, 1851 | | |
| John Appleton | Democratic | March 4, 1851 – March 3, 1853 | | |
| Samuel Mayall | Democratic | March 4, 1853 – March 3, 1855 | | |
| John J. Perry | Opposition | March 4, 1855 – March 3, 1857 | | |
| Charles J. Gilman | Republican | March 4, 1857 – March 3, 1859 | | |
| John J. Perry | Republican | March 4, 1859 – March 3, 1861 | | |
| Charles W. Walton | Republican | March 4, 1861 – May 26, 1862 | | resigned on appointment as associate justice of Maine Supreme Judicial Court |
| Vacant | May 26, 1862 – December 1, 1862 |
| Thomas Fessenden | Republican | December 1, 1862 – March 3, 1863 | | |
| Sidney Perham | Republican | March 4, 1863 – March 3, 1869 | | |
| Samuel Plummer Morrill | Republican | March 4, 1869 – March 3, 1871 | | |
| William P. Frye | Republican | March 4, 1871 – March 17, 1881 | | resigned after election to US Senate |
| Vacant | March 17, 1881 – September 12, 1881 |
| Nelson Dingley, Jr. | Republican | September 12, 1881 – March 3, 1883 | | redistricted to At-large district |
| At-large districts used | 1883 – 1885 |
| Nelson Dingley, Jr. | Republican | March 3, 1885 – January 13, 1899 | | redistricted from At-large district, died |
| Vacant | January 13, 1899 – June 19, 1899 |
| Charles E. Littlefield | Republican | June 19, 1899 – September 30, 1908 | | resigned |
| Vacant | September 30, 1908 – November 3, 1908 |
| John P. Swasey | Republican | November 3, 1908 – March 3, 1911 | | |
| Daniel J. McGillicuddy | Democratic | March 4, 1911 – March 3, 1917 | | |
| Wallace H. White, Jr. | Republican | March 4, 1917 – March 3, 1931 | | |
| Donald B. Partridge | Republican | March 4, 1931 – March 3, 1933 | | |
| Edward C. Moran, Jr. | Democratic | March 4, 1933 – January 3, 1937 | | |
| Clyde H. Smith | Republican | January 3, 1937 – April 8, 1940 | | died |
| Vacant | April 8, 1940 – June 3, 1940 |
| Margaret Chase Smith | Republican | June 3, 1940 – January 3, 1949 | | retired to run for US Senate |
| Charles P. Nelson | Republican | January 3, 1949 – January 3, 1957 | | |
| Frank M. Coffin | Democratic | 1957 – 1961 | | |
| Stanley R. Tupper | Republican | January 3, 1961 – January 3, 1963 | | redistricted from 1st district |
| Clifford G. McIntire | Republican | January 3, 1963 – January 3, 1965 | | redistricted from 3rd district |
| William Hathaway | Democratic | January 3, 1965 – January 3, 1973 | | retired to run for US Senate |
| William Cohen | Republican | January 3, 1973 – January 3, 1979 | | retired to run for US Senate |
| Olympia Snowe | Republican | January 3, 1979 – January 3, 1995 | | retired to run for US Senate |
| John Baldacci | Democratic | January 3, 1995 – January 3, 2003 | | retired to run for Governor |
| Mike Michaud | Democratic | January 3, 2003 – present | | incumbent |
| Representative | Party | Years | District home | Note |
