# List of United States senators from Maine

Maine was admitted to the Union on March 15, 1820. The state's U.S. senators belong to class 1 and class 2. Republican Susan Collins (first elected in 1996) and Independent Angus King (first elected in 2012) are Maine's current U.S. senators, making Maine one of four states to have a split United States Senate delegation. William P. Frye was Maine's longest serving senator (1881–1911). Maine is one of fourteen states alongside California, Colorado, Georgia, Hawaii, Idaho, Louisiana, Massachusetts, Minnesota, Missouri, Nevada, Pennsylvania, South Dakota, and Utah to have a younger senior senator and an older junior senator.

## List of senators

| Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2000, 2006, 2012, and 2018. The next election will be in 2024. | Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2000, 2006, 2012, and 2018. The next election will be in 2024. | Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2000, 2006, 2012, and 2018. The next election will be in 2024. | Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2000, 2006, 2012, and 2018. The next election will be in 2024. | Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2000, 2006, 2012, and 2018. The next election will be in 2024. | Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2000, 2006, 2012, and 2018. The next election will be in 2024. | C | Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. |
| # | Senator | Party | Dates in office | Electoral history | T | C | T | Electoral history | Dates in office | Party | Senator | # |
| 1 | John Holmes | Democratic- Republican | Jun 13, 1820 – Mar 3, 1827 | Elected in 1820. | 1 | 16th | 1 | Elected in 1820. | Jun 14, 1820 – Mar 3, 1829 | Democratic- Republican | John Chandler | 1 |
| 1 | John Holmes | Democratic- Republican | Jun 13, 1820 – Mar 3, 1827 | Re-elected in 1821. | 2 | 17th | 1 | Elected in 1820. | Jun 14, 1820 – Mar 3, 1829 | Democratic- Republican | John Chandler | 1 |
| 1 | John Holmes | Democratic- Republican | Jun 13, 1820 – Mar 3, 1827 | Re-elected in 1821. | 2 | 18th | 2 | Re-elected in 1823.Retired. | Jun 14, 1820 – Mar 3, 1829 | Democratic- Republican | John Chandler | 1 |
| 1 | John Holmes | National Republican | Jun 13, 1820 – Mar 3, 1827 | Re-elected in 1821. | 2 | 19th | 2 | Re-elected in 1823.Retired. | Jun 14, 1820 – Mar 3, 1829 | Jacksonian | John Chandler | 1 |
| 2 | Albion Parris | Jacksonian | Mar 4, 1827 – Aug 26, 1828 | Elected in 1827.Resigned to become a judge on the Maine Supreme Judicial Court. | 3 | 20th | 2 | Re-elected in 1823.Retired. | Jun 14, 1820 – Mar 3, 1829 | Jacksonian | John Chandler | 1 |
| Vacant | Vacant | Vacant | Aug 26, 1828 – Jan 15, 1829 | | 3 | 20th | 2 | Re-elected in 1823.Retired. | Jun 14, 1820 – Mar 3, 1829 | Jacksonian | John Chandler | 1 |
| 3 | John Holmes | National Republican | Jan 15, 1829 – Mar 3, 1833 | Elected to finish Parris's term.Retired. | 3 | 20th | 2 | Re-elected in 1823.Retired. | Jun 14, 1820 – Mar 3, 1829 | Jacksonian | John Chandler | 1 |
| 3 | John Holmes | National Republican | Jan 15, 1829 – Mar 3, 1833 | Elected to finish Parris's term.Retired. | 3 | 21st | 3 | Elected in 1829.Resigned. | Mar 4, 1829 – Jan 1, 1835 | National Republican | Peleg Sprague | 2 |
| 3 | John Holmes | National Republican | Jan 15, 1829 – Mar 3, 1833 | Elected to finish Parris's term.Retired. | 3 | 22nd | 3 | Elected in 1829.Resigned. | Mar 4, 1829 – Jan 1, 1835 | National Republican | Peleg Sprague | 2 |
| 4 | Ether Shepley | Jacksonian | Mar 4, 1833 – Mar 3, 1836 | Elected in 1833.Resigned to become Justice of the Maine Supreme Judicial Court. | 4 | 23rd | 3 | Elected in 1829.Resigned. | Mar 4, 1829 – Jan 1, 1835 | National Republican | Peleg Sprague | 2 |
| 4 | Ether Shepley | Jacksonian | Mar 4, 1833 – Mar 3, 1836 | Elected in 1833.Resigned to become Justice of the Maine Supreme Judicial Court. | 4 | 23rd | 3 | | Jan 1, 1835 – Jan 20, 1835 | Vacant | Vacant | Vacant |
| 4 | Ether Shepley | Jacksonian | Mar 4, 1833 – Mar 3, 1836 | Elected in 1833.Resigned to become Justice of the Maine Supreme Judicial Court. | 4 | 23rd | 3 | Elected to finish Sprague's term, having already been elected to the next term. | Jan 20, 1835 – Mar 3, 1841 | Jacksonian | John Ruggles | 3 |
| 4 | Ether Shepley | Jacksonian | Mar 4, 1833 – Mar 3, 1836 | Elected in 1833.Resigned to become Justice of the Maine Supreme Judicial Court. | 4 | 24th | 4 | Elected in 1835.Lost re-election. | Jan 20, 1835 – Mar 3, 1841 | Jacksonian | John Ruggles | 3 |
| 5 | Judah Dana | Jacksonian | Mar 4, 1836 – Mar 3, 1837 | Appointed to continue Shepley's term.Either lost election to finish the term or retired when elected successor qualified. | 4 | 24th | 4 | Elected in 1835.Lost re-election. | Jan 20, 1835 – Mar 3, 1841 | Jacksonian | John Ruggles | 3 |
| 6 | Reuel Williams | Democratic | Mar 4, 1837 – Feb 15, 1843 | Elected to finish Shepley's term. | 4 | 25th | 4 | Elected in 1835.Lost re-election. | Jan 20, 1835 – Mar 3, 1841 | Democratic | John Ruggles | 3 |
| 6 | Reuel Williams | Democratic | Mar 4, 1837 – Feb 15, 1843 | Re-elected in 1839.Resigned. | 5 | 26th | 4 | Elected in 1835.Lost re-election. | Jan 20, 1835 – Mar 3, 1841 | Democratic | John Ruggles | 3 |
| 6 | Reuel Williams | Democratic | Mar 4, 1837 – Feb 15, 1843 | Re-elected in 1839.Resigned. | 5 | 27th | 5 | Elected in 1840.Lost re-election. | Mar 4, 1841 – Mar 3, 1847 | Whig | George Evans | 4 |
| Vacant | Vacant | Vacant | Feb 15, 1843 – Dec 4, 1843 | | 5 | 27th | 5 | Elected in 1840.Lost re-election. | Mar 4, 1841 – Mar 3, 1847 | Whig | George Evans | 4 |
| Vacant | Vacant | Vacant | Feb 15, 1843 – Dec 4, 1843 | | 5 | 28th | 5 | Elected in 1840.Lost re-election. | Mar 4, 1841 – Mar 3, 1847 | Whig | George Evans | 4 |
| 7 | John Fairfield | Democratic | Dec 4, 1843 – Dec 24, 1847 | Elected to finish Williams's term. | 5 | 28th | 5 | Elected in 1840.Lost re-election. | Mar 4, 1841 – Mar 3, 1847 | Whig | George Evans | 4 |
| 7 | John Fairfield | Democratic | Dec 4, 1843 – Dec 24, 1847 | Re-elected in 1844 or 1845.Died. | 6 | 29th | 5 | Elected in 1840.Lost re-election. | Mar 4, 1841 – Mar 3, 1847 | Whig | George Evans | 4 |
| 7 | John Fairfield | Democratic | Dec 4, 1843 – Dec 24, 1847 | Re-elected in 1844 or 1845.Died. | 6 | 30th | 6 | Elected in 1846.Retired. | Mar 4, 1847 – Mar 3, 1853 | Democratic | James W. Bradbury | 5 |
| Vacant | Vacant | Vacant | Dec 24, 1847 – Jan 5, 1848 | | 6 | 30th | 6 | Elected in 1846.Retired. | Mar 4, 1847 – Mar 3, 1853 | Democratic | James W. Bradbury | 5 |
| 8 | Wyman B. S. Moor | Democratic | Jan 5, 1848 – June 7, 1848 | Appointed to continue Fairfield's term.Successor elected. | 6 | 30th | 6 | Elected in 1846.Retired. | Mar 4, 1847 – Mar 3, 1853 | Democratic | James W. Bradbury | 5 |
| 9 | Hannibal Hamlin | Democratic | Jun 8, 1848 – Jan 7, 1857 | Elected to finish Fairfield's term. | 6 | 30th | 6 | Elected in 1846.Retired. | Mar 4, 1847 – Mar 3, 1853 | Democratic | James W. Bradbury | 5 |
| 9 | Hannibal Hamlin | Democratic | Jun 8, 1848 – Jan 7, 1857 | Elected to finish Fairfield's term. | 6 | 31st | 6 | Elected in 1846.Retired. | Mar 4, 1847 – Mar 3, 1853 | Democratic | James W. Bradbury | 5 |
| 9 | Hannibal Hamlin | Democratic | Jun 8, 1848 – Jan 7, 1857 | Re-elected in 1851.Changed parties in 1856.Resigned to become Governor of Maine. | 7 | 32nd | 6 | Elected in 1846.Retired. | Mar 4, 1847 – Mar 3, 1853 | Democratic | James W. Bradbury | 5 |
| 9 | Hannibal Hamlin | Democratic | Jun 8, 1848 – Jan 7, 1857 | Re-elected in 1851.Changed parties in 1856.Resigned to become Governor of Maine. | 7 | 33rd | 7 | Legislature failed to elect. | Mar 4, 1853 – Feb 10, 1854 | Vacant | Vacant | Vacant |
| 9 | Hannibal Hamlin | Democratic | Jun 8, 1848 – Jan 7, 1857 | Re-elected in 1851.Changed parties in 1856.Resigned to become Governor of Maine. | 7 | 33rd | 7 | Elected to finish term. | Feb 10, 1854 – Jul 1, 1864 | Whig | William P. Fessenden | 6 |
| 9 | Hannibal Hamlin | Democratic | Jun 8, 1848 – Jan 7, 1857 | Re-elected in 1851.Changed parties in 1856.Resigned to become Governor of Maine. | 7 | 34th | 7 | Elected to finish term. | Feb 10, 1854 – Jul 1, 1864 | Whig | William P. Fessenden | 6 |
| 9 | Hannibal Hamlin | Republican | Jun 8, 1848 – Jan 7, 1857 | Re-elected in 1851.Changed parties in 1856.Resigned to become Governor of Maine. | 7 | 34th | 7 | Elected to finish term. | Feb 10, 1854 – Jul 1, 1864 | Whig | William P. Fessenden | 6 |
| Vacant | Vacant | Vacant | Jan 7, 1857 – Jan 16, 1857 | | 7 | 34th | 7 | Elected to finish term. | Feb 10, 1854 – Jul 1, 1864 | Whig | William P. Fessenden | 6 |
| 10 | Amos Nourse | Republican | Jan 16, 1857 – Mar 3, 1857 | Elected to finish Hamlin's term. | 7 | 34th | 7 | Elected to finish term. | Feb 10, 1854 – Jul 1, 1864 | Whig | William P. Fessenden | 6 |
| 11 | Hannibal Hamlin | Republican | Mar 4, 1857 – Jan 17, 1861 | Elected in 1857.Resigned to become Vice President of the United States. | 8 | 35th | 7 | Elected to finish term. | Feb 10, 1854 – Jul 1, 1864 | Republican | William P. Fessenden | 6 |
| 11 | Hannibal Hamlin | Republican | Mar 4, 1857 – Jan 17, 1861 | Elected in 1857.Resigned to become Vice President of the United States. | 8 | 36th | 8 | Re-elected in 1859.Resigned to become U.S. Secretary of the Treasury. | Feb 10, 1854 – Jul 1, 1864 | Republican | William P. Fessenden | 6 |
| 12 | Lot M. Morrill | Republican | Jan 17, 1861 – Mar 3, 1869 | Elected to finish Hamlin's term. | 8 | 36th | 8 | Re-elected in 1859.Resigned to become U.S. Secretary of the Treasury. | Feb 10, 1854 – Jul 1, 1864 | Republican | William P. Fessenden | 6 |
| 12 | Lot M. Morrill | Republican | Jan 17, 1861 – Mar 3, 1869 | Elected to finish Hamlin's term. | 8 | 37th | 8 | Re-elected in 1859.Resigned to become U.S. Secretary of the Treasury. | Feb 10, 1854 – Jul 1, 1864 | Republican | William P. Fessenden | 6 |
| 12 | Lot M. Morrill | Republican | Jan 17, 1861 – Mar 3, 1869 | Re-elected in 1863.Lost re-election. | 9 | 38th | 8 | Re-elected in 1859.Resigned to become U.S. Secretary of the Treasury. | Feb 10, 1854 – Jul 1, 1864 | Republican | William P. Fessenden | 6 |
| 12 | Lot M. Morrill | Republican | Jan 17, 1861 – Mar 3, 1869 | Re-elected in 1863.Lost re-election. | 9 | 38th | 8 | | Jul 1, 1864 – Oct 27, 1864 | Vacant | Vacant | Vacant |
| 12 | Lot M. Morrill | Republican | Jan 17, 1861 – Mar 3, 1869 | Re-elected in 1863.Lost re-election. | 9 | 38th | 8 | Appointed to continue Fessenden's term.Elected in 1865 to finish Fessenden's term.Retired. | Oct 27, 1864 – Mar 3, 1865 | Republican | Nathan A. Farwell | 7 |
| 12 | Lot M. Morrill | Republican | Jan 17, 1861 – Mar 3, 1869 | Re-elected in 1863.Lost re-election. | 9 | 39th | 9 | Elected in 1864 or 1865.Died. | Mar 4, 1865 – Sep 8, 1869 | Republican | William P. Fessenden | 8 |
| 12 | Lot M. Morrill | Republican | Jan 17, 1861 – Mar 3, 1869 | Re-elected in 1863.Lost re-election. | 9 | 40th | 9 | Elected in 1864 or 1865.Died. | Mar 4, 1865 – Sep 8, 1869 | Republican | William P. Fessenden | 8 |
| 13 | Hannibal Hamlin | Republican | Mar 4, 1869 – Mar 3, 1881 | Elected in 1869. | 10 | 41st | 9 | Elected in 1864 or 1865.Died. | Mar 4, 1865 – Sep 8, 1869 | Republican | William P. Fessenden | 8 |
| 13 | Hannibal Hamlin | Republican | Mar 4, 1869 – Mar 3, 1881 | Elected in 1869. | 10 | 41st | 9 | | Sep 8, 1869 – Oct 30, 1869 | Vacant | Vacant | Vacant |
| 13 | Hannibal Hamlin | Republican | Mar 4, 1869 – Mar 3, 1881 | Elected in 1869. | 10 | 41st | 9 | Appointed to finish Fessenden's term.Elected in 1870 to finish Fessenden's term. | Oct 30, 1869 – Jul 7, 1876 | Republican | Lot M. Morrill | 9 |
| 13 | Hannibal Hamlin | Republican | Mar 4, 1869 – Mar 3, 1881 | Elected in 1869. | 10 | 42nd | 10 | Re-election year unknown.Resigned to become U.S. Secretary of the Treasury. | Oct 30, 1869 – Jul 7, 1876 | Republican | Lot M. Morrill | 9 |
| 13 | Hannibal Hamlin | Republican | Mar 4, 1869 – Mar 3, 1881 | Elected in 1869. | 10 | 43rd | 10 | Re-election year unknown.Resigned to become U.S. Secretary of the Treasury. | Oct 30, 1869 – Jul 7, 1876 | Republican | Lot M. Morrill | 9 |
| 13 | Hannibal Hamlin | Republican | Mar 4, 1869 – Mar 3, 1881 | Re-elected in 1875.Retired. | 11 | 44th | 10 | Re-election year unknown.Resigned to become U.S. Secretary of the Treasury. | Oct 30, 1869 – Jul 7, 1876 | Republican | Lot M. Morrill | 9 |
| 13 | Hannibal Hamlin | Republican | Mar 4, 1869 – Mar 3, 1881 | Re-elected in 1875.Retired. | 11 | 44th | 10 | | Jul 7, 1876 – Jul 10, 1876 | Vacant | Vacant | Vacant |
| 13 | Hannibal Hamlin | Republican | Mar 4, 1869 – Mar 3, 1881 | Re-elected in 1875.Retired. | 11 | 44th | 10 | Appointed to finish Morrill's term.Elected in 1877 to finish Morrill's term. | Jul 10, 1876 – Mar 5, 1881 | Republican | James G. Blaine | 10 |
| 13 | Hannibal Hamlin | Republican | Mar 4, 1869 – Mar 3, 1881 | Re-elected in 1875.Retired. | 11 | 45th | 11 | Elected to full term in 1877.Resigned to become U.S. Secretary of State. | Jul 10, 1876 – Mar 5, 1881 | Republican | James G. Blaine | 10 |
| 13 | Hannibal Hamlin | Republican | Mar 4, 1869 – Mar 3, 1881 | Re-elected in 1875.Retired. | 11 | 46th | 11 | Elected to full term in 1877.Resigned to become U.S. Secretary of State. | Jul 10, 1876 – Mar 5, 1881 | Republican | James G. Blaine | 10 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Elected in 1881. | 12 | 47th | 11 | Elected to full term in 1877.Resigned to become U.S. Secretary of State. | Jul 10, 1876 – Mar 5, 1881 | Republican | James G. Blaine | 10 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Elected in 1881. | 12 | 47th | 11 | | Mar 5, 1881 – Mar 18, 1881 | Vacant | Vacant | Vacant |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Elected in 1881. | 12 | 47th | 11 | Elected to finish Blaine's term | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Elected in 1881. | 12 | 48th | 12 | Re-elected in 1883. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Elected in 1881. | 12 | 49th | 12 | Re-elected in 1883. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Re-elected in 1887. | 13 | 50th | 12 | Re-elected in 1883. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Re-elected in 1887. | 13 | 51st | 13 | Re-elected in 1889. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Re-elected in 1887. | 13 | 52nd | 13 | Re-elected in 1889. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Re-elected in 1893. | 14 | 53rd | 13 | Re-elected in 1889. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Re-elected in 1893. | 14 | 54th | 14 | Re-elected in 1895. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Re-elected in 1893. | 14 | 55th | 14 | Re-elected in 1895. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Re-elected in 1899. | 15 | 56th | 14 | Re-elected in 1895. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Re-elected in 1899. | 15 | 57th | 15 | Re-elected in 1901. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Re-elected in 1899. | 15 | 58th | 15 | Re-elected in 1901. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Re-elected in 1905.Retired. | 16 | 59th | 15 | Re-elected in 1901. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Re-elected in 1905.Retired. | 16 | 60th | 16 | Re-elected in 1907.Died. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 14 | Eugene Hale | Republican | Mar 4, 1881 – Mar 3, 1911 | Re-elected in 1905.Retired. | 16 | 61st | 16 | Re-elected in 1907.Died. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 15 | Charles F. Johnson | Democratic | Mar 4, 1911 – Mar 3, 1917 | Elected in 1911.Lost re-election. | 17 | 62nd | 16 | Re-elected in 1907.Died. | Mar 18, 1881 – Aug 8, 1911 | Republican | William P. Frye | 11 |
| 15 | Charles F. Johnson | Democratic | Mar 4, 1911 – Mar 3, 1917 | Elected in 1911.Lost re-election. | 17 | 62nd | 16 | | Aug 8, 1911 – Sep 23, 1911 | Vacant | Vacant | Vacant |
| 15 | Charles F. Johnson | Democratic | Mar 4, 1911 – Mar 3, 1917 | Elected in 1911.Lost re-election. | 17 | 62nd | 16 | Appointed to continue Frye's term.Elected in 1912 to finish Frye's term.Lost re-election. | Sep 23, 1911 – Mar 3, 1913 | Democratic | Obadiah Gardner | 12 |
| 15 | Charles F. Johnson | Democratic | Mar 4, 1911 – Mar 3, 1917 | Elected in 1911.Lost re-election. | 17 | 63rd | 17 | Elected in 1913.Died. | Mar 4, 1913 – Jun 16, 1916 | Republican | Edwin C. Burleigh | 13 |
| 15 | Charles F. Johnson | Democratic | Mar 4, 1911 – Mar 3, 1917 | Elected in 1911.Lost re-election. | 17 | 64th | 17 | Elected in 1913.Died. | Mar 4, 1913 – Jun 16, 1916 | Republican | Edwin C. Burleigh | 13 |
| 15 | Charles F. Johnson | Democratic | Mar 4, 1911 – Mar 3, 1917 | Elected in 1911.Lost re-election. | 17 | 64th | 17 | | Jun 16, 1916 – Sep 12, 1916 | Vacant | Vacant | Vacant |
| 15 | Charles F. Johnson | Democratic | Mar 4, 1911 – Mar 3, 1917 | Elected in 1911.Lost re-election. | 17 | 64th | 17 | Elected to finish Burleigh's term. | Sep 12, 1916 – Aug 23, 1926 | Republican | Bert M. Fernald | 14 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Elected in 1916. | 18 | 65th | 17 | Elected to finish Burleigh's term. | Sep 12, 1916 – Aug 23, 1926 | Republican | Bert M. Fernald | 14 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Elected in 1916. | 18 | 66th | 18 | Re-elected in 1918. | Sep 12, 1916 – Aug 23, 1926 | Republican | Bert M. Fernald | 14 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Elected in 1916. | 18 | 67th | 18 | Re-elected in 1918. | Sep 12, 1916 – Aug 23, 1926 | Republican | Bert M. Fernald | 14 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Re-elected in 1922. | 19 | 68th | 18 | Re-elected in 1918. | Sep 12, 1916 – Aug 23, 1926 | Republican | Bert M. Fernald | 14 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Re-elected in 1922. | 19 | 69th | 19 | Re-elected in 1924.Died. | Sep 12, 1916 – Aug 23, 1926 | Republican | Bert M. Fernald | 14 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Re-elected in 1922. | 19 | 69th | 19 | | Aug 23, 1926 – Nov 30, 1926 | Vacant | Vacant | Vacant |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Re-elected in 1922. | 19 | 69th | 19 | Elected to finish Fernald's term.Retired. | Nov 30, 1926 – Mar 3, 1931 | Republican | Arthur R. Gould | 15 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Re-elected in 1922. | 19 | 70th | 19 | Elected to finish Fernald's term.Retired. | Nov 30, 1926 – Mar 3, 1931 | Republican | Arthur R. Gould | 15 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Re-elected in 1928. | 20 | 71st | 19 | Elected to finish Fernald's term.Retired. | Nov 30, 1926 – Mar 3, 1931 | Republican | Arthur R. Gould | 15 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Re-elected in 1928. | 20 | 72nd | 20 | Elected in 1930. | Mar 4, 1931 – Jan 3, 1949 | Republican | Wallace H. White | 16 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Re-elected in 1928. | 20 | 73rd | 20 | Elected in 1930. | Mar 4, 1931 – Jan 3, 1949 | Republican | Wallace H. White | 16 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Re-elected in 1934.Retired. | 21 | 74th | 20 | Elected in 1930. | Mar 4, 1931 – Jan 3, 1949 | Republican | Wallace H. White | 16 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Re-elected in 1934.Retired. | 21 | 75th | 21 | Re-elected in 1936. | Mar 4, 1931 – Jan 3, 1949 | Republican | Wallace H. White | 16 |
| 16 | Frederick Hale | Republican | Mar 4, 1917 – Jan 3, 1941 | Re-elected in 1934.Retired. | 21 | 76th | 21 | Re-elected in 1936. | Mar 4, 1931 – Jan 3, 1949 | Republican | Wallace H. White | 16 |
| 17 | Owen Brewster | Republican | Jan 3, 1941 – Dec 31, 1952 | Elected in 1940. | 22 | 77th | 21 | Re-elected in 1936. | Mar 4, 1931 – Jan 3, 1949 | Republican | Wallace H. White | 16 |
| 17 | Owen Brewster | Republican | Jan 3, 1941 – Dec 31, 1952 | Elected in 1940. | 22 | 78th | 22 | Re-elected in 1942.Retired. | Mar 4, 1931 – Jan 3, 1949 | Republican | Wallace H. White | 16 |
| 17 | Owen Brewster | Republican | Jan 3, 1941 – Dec 31, 1952 | Elected in 1940. | 22 | 79th | 22 | Re-elected in 1942.Retired. | Mar 4, 1931 – Jan 3, 1949 | Republican | Wallace H. White | 16 |
| 17 | Owen Brewster | Republican | Jan 3, 1941 – Dec 31, 1952 | Re-elected in 1946.Resigned, having already lost renomination. | 23 | 80th | 22 | Re-elected in 1942.Retired. | Mar 4, 1931 – Jan 3, 1949 | Republican | Wallace H. White | 16 |
| 17 | Owen Brewster | Republican | Jan 3, 1941 – Dec 31, 1952 | Re-elected in 1946.Resigned, having already lost renomination. | 23 | 81st | 23 | Elected in 1948. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| 17 | Owen Brewster | Republican | Jan 3, 1941 – Dec 31, 1952 | Re-elected in 1946.Resigned, having already lost renomination. | 23 | 82nd | 23 | Elected in 1948. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| Vacant | Vacant | Vacant | Dec 31, 1952 – Jan 3, 1953 | | 23 | 82nd | 23 | Elected in 1948. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| 18 | Frederick G. Payne | Republican | Jan 3, 1953 – Jan 3, 1959 | Elected in 1952.Lost re-election. | 24 | 83rd | 23 | Elected in 1948. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| 18 | Frederick G. Payne | Republican | Jan 3, 1953 – Jan 3, 1959 | Elected in 1952.Lost re-election. | 24 | 84th | 24 | Re-elected in 1954. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| 18 | Frederick G. Payne | Republican | Jan 3, 1953 – Jan 3, 1959 | Elected in 1952.Lost re-election. | 24 | 85th | 24 | Re-elected in 1954. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| 19 | Edmund Muskie | Democratic | Jan 3, 1959 – May 7, 1980 | Elected in 1958. | 25 | 86th | 24 | Re-elected in 1954. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| 19 | Edmund Muskie | Democratic | Jan 3, 1959 – May 7, 1980 | Elected in 1958. | 25 | 87th | 25 | Re-elected in 1960. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| 19 | Edmund Muskie | Democratic | Jan 3, 1959 – May 7, 1980 | Elected in 1958. | 25 | 88th | 25 | Re-elected in 1960. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| 19 | Edmund Muskie | Democratic | Jan 3, 1959 – May 7, 1980 | Re-elected in 1964. | 26 | 89th | 25 | Re-elected in 1960. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| 19 | Edmund Muskie | Democratic | Jan 3, 1959 – May 7, 1980 | Re-elected in 1964. | 26 | 90th | 26 | Re-elected in 1966.Lost re-election. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| 19 | Edmund Muskie | Democratic | Jan 3, 1959 – May 7, 1980 | Re-elected in 1964. | 26 | 91st | 26 | Re-elected in 1966.Lost re-election. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| 19 | Edmund Muskie | Democratic | Jan 3, 1959 – May 7, 1980 | Re-elected in 1970. | 27 | 92nd | 26 | Re-elected in 1966.Lost re-election. | Jan 3, 1949 – Jan 3, 1973 | Republican | Margaret Chase Smith | 17 |
| 19 | Edmund Muskie | Democratic | Jan 3, 1959 – May 7, 1980 | Re-elected in 1970. | 27 | 93rd | 27 | Elected in 1972.Lost re-election. | Jan 3, 1973 – Jan 3, 1979 | Democratic | Bill Hathaway | 18 |
| 19 | Edmund Muskie | Democratic | Jan 3, 1959 – May 7, 1980 | Re-elected in 1970. | 27 | 94th | 27 | Elected in 1972.Lost re-election. | Jan 3, 1973 – Jan 3, 1979 | Democratic | Bill Hathaway | 18 |
| 19 | Edmund Muskie | Democratic | Jan 3, 1959 – May 7, 1980 | Re-elected in 1976.Resigned to become U.S. Secretary of State. | 28 | 95th | 27 | Elected in 1972.Lost re-election. | Jan 3, 1973 – Jan 3, 1979 | Democratic | Bill Hathaway | 18 |
| 19 | Edmund Muskie | Democratic | Jan 3, 1959 – May 7, 1980 | Re-elected in 1976.Resigned to become U.S. Secretary of State. | 28 | 96th | 28 | Elected in 1978. | Jan 3, 1979 – Jan 3, 1997 | Republican | William Cohen | 19 |
| Vacant | Vacant | Vacant | May 7, 1980 – May 19, 1980 | | 28 | 96th | 28 | Elected in 1978. | Jan 3, 1979 – Jan 3, 1997 | Republican | William Cohen | 19 |
| 20 | George J. Mitchell | Democratic | May 19, 1980 – Jan 3, 1995 | Appointed to finish Muskie's term. | 28 | 96th | 28 | Elected in 1978. | Jan 3, 1979 – Jan 3, 1997 | Republican | William Cohen | 19 |
| 20 | George J. Mitchell | Democratic | May 19, 1980 – Jan 3, 1995 | Appointed to finish Muskie's term. | 28 | 97th | 28 | Elected in 1978. | Jan 3, 1979 – Jan 3, 1997 | Republican | William Cohen | 19 |
| 20 | George J. Mitchell | Democratic | May 19, 1980 – Jan 3, 1995 | Elected to full term in 1982. | 29 | 98th | 28 | Elected in 1978. | Jan 3, 1979 – Jan 3, 1997 | Republican | William Cohen | 19 |
| 20 | George J. Mitchell | Democratic | May 19, 1980 – Jan 3, 1995 | Elected to full term in 1982. | 29 | 99th | 29 | Re-elected in 1984. | Jan 3, 1979 – Jan 3, 1997 | Republican | William Cohen | 19 |
| 20 | George J. Mitchell | Democratic | May 19, 1980 – Jan 3, 1995 | Elected to full term in 1982. | 29 | 100th | 29 | Re-elected in 1984. | Jan 3, 1979 – Jan 3, 1997 | Republican | William Cohen | 19 |
| 20 | George J. Mitchell | Democratic | May 19, 1980 – Jan 3, 1995 | Re-elected in 1988.Retired. | 30 | 101st | 29 | Re-elected in 1984. | Jan 3, 1979 – Jan 3, 1997 | Republican | William Cohen | 19 |
| 20 | George J. Mitchell | Democratic | May 19, 1980 – Jan 3, 1995 | Re-elected in 1988.Retired. | 30 | 102nd | 30 | Re-elected in 1990.Retired. | Jan 3, 1979 – Jan 3, 1997 | Republican | William Cohen | 19 |
| 20 | George J. Mitchell | Democratic | May 19, 1980 – Jan 3, 1995 | Re-elected in 1988.Retired. | 30 | 103rd | 30 | Re-elected in 1990.Retired. | Jan 3, 1979 – Jan 3, 1997 | Republican | William Cohen | 19 |
| 21 | Olympia Snowe | Republican | Jan 3, 1995 – Jan 3, 2013 | Elected in 1994. | 31 | 104th | 30 | Re-elected in 1990.Retired. | Jan 3, 1979 – Jan 3, 1997 | Republican | William Cohen | 19 |
| 21 | Olympia Snowe | Republican | Jan 3, 1995 – Jan 3, 2013 | Elected in 1994. | 31 | 105th | 31 | Elected in 1996. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 21 | Olympia Snowe | Republican | Jan 3, 1995 – Jan 3, 2013 | Elected in 1994. | 31 | 106th | 31 | Elected in 1996. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 21 | Olympia Snowe | Republican | Jan 3, 1995 – Jan 3, 2013 | Re-elected in 2000. | 32 | 107th | 31 | Elected in 1996. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 21 | Olympia Snowe | Republican | Jan 3, 1995 – Jan 3, 2013 | Re-elected in 2000. | 32 | 108th | 32 | Re-elected in 2002. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 21 | Olympia Snowe | Republican | Jan 3, 1995 – Jan 3, 2013 | Re-elected in 2000. | 32 | 109th | 32 | Re-elected in 2002. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 21 | Olympia Snowe | Republican | Jan 3, 1995 – Jan 3, 2013 | Re-elected in 2006.Retired. | 33 | 110th | 32 | Re-elected in 2002. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 21 | Olympia Snowe | Republican | Jan 3, 1995 – Jan 3, 2013 | Re-elected in 2006.Retired. | 33 | 111th | 33 | Re-elected in 2008. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 21 | Olympia Snowe | Republican | Jan 3, 1995 – Jan 3, 2013 | Re-elected in 2006.Retired. | 33 | 112th | 33 | Re-elected in 2008. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 22 | Angus King | Independent | Jan 3, 2013 – present | Elected in 2012. | 34 | 113th | 33 | Re-elected in 2008. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 22 | Angus King | Independent | Jan 3, 2013 – present | Elected in 2012. | 34 | 114th | 34 | Re-elected in 2014. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 22 | Angus King | Independent | Jan 3, 2013 – present | Elected in 2012. | 34 | 115th | 34 | Re-elected in 2014. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 22 | Angus King | Independent | Jan 3, 2013 – present | Re-elected in 2018. | 35 | 116th | 34 | Re-elected in 2014. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 22 | Angus King | Independent | Jan 3, 2013 – present | Re-elected in 2018. | 35 | 117th | 35 | Re-elected in 2020. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 22 | Angus King | Independent | Jan 3, 2013 – present | Re-elected in 2018. | 35 | 118th | 35 | Re-elected in 2020. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 22 | Angus King | Independent | Jan 3, 2013 – present | Re-elected in 2024. | 36 | 119th | 35 | Re-elected in 2020. | Jan 3, 1997 – present | Republican | Susan Collins | 20 |
| 22 | Angus King | Independent | Jan 3, 2013 – present | Re-elected in 2024. | 36 | 120th | 36 | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. |
| 22 | Angus King | Independent | Jan 3, 2013 – present | Re-elected in 2024. | 36 | 121st | 36 | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 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. | 37 | 122nd | 36 | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 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 2 | Class 2 | Class 2 | Class 2 | Class 2 | Class 2 |