| CONGRESS | SENATOR | TERM BEGAN | TERM ENDED | COMMENTS |
|---|---|---|---|---|
| Class 1 | ||||
| 2nd-4th | Moses Robinson (ANTI-ADMIN, R) | Oct. 17, 1791 | Oct. 15, 1796 | Resigned |
| 4th-5th | Isaac Tichenor (F) | Oct. 18, 1796 | Oct. 17, 1797 | Resigned |
| 5th-7th | Nathaniel Chipman (F) | Oct. 17, 1797 | Mar. 3, 1803 | |
| 8th-10th | Israel Smith (R) | Mar. 4, 1803 | Oct. 1, 1807 | Resigned |
| 10th-13th | Jonathan Robinson (R) | Oct. 10, 1807 | Mar. 3, 1815 | |
| 14th-16th | Isaac Tichenor (F) | Mar. 4, 1815 | Mar. 3, 1821 | |
| 17th-22nd | Horatio Seymour (R, ADAMS-CLAY R, ADAMS, AJ) | Mar. 4, 1821 | Mar. 3, 1833 | |
| 23rd-25th | Benjamin Swift (AJ, W) | Mar. 4, 1833 | Mar. 3, 1839 | |
| 26th-31st | Samuel S. Phelps (W) | Mar. 4, 1839 | Mar. 3, 1851 | |
| 32nd-39th | Solomon Foot (W, OP, R) | Mar. 4, 1851 | Mar. 28, 1866 | Died |
| 39th-52nd | George F. Edmunds (R) | Apr. 3, 1866 | Nov. 1, 1891 | Appointed, then elected; resigned |
| 52nd-60th | Redfield Proctor (R) | Nov. 2, 1891 | Mar. 4, 1908 | Appointed, then elected; died |
| 60th | John W. Stewart (R) | Mar. 24, 1908 | Oct. 20, 1908 | Appointed |
| 60th-67th | Carroll S. Page (R) | Oct. 21, 1908 | Mar. 3, 1923 | |
| 68th-71st | Frank L. Greene (R) | Mar. 4, 1923 | Dec. 17, 1930 | Died |
| 71st-72nd | Frank C. Partridge (R) | Dec. 23, 1930 | Mar. 31, 1931 | Appointed |
| 72nd-79th | Warren R. Austin (R) | Apr. 1, 1931 | Aug. 2, 1946 | Resigned |
| 79th-85th | Ralph E. Flanders (R) | Nov. 1, 1946 | Jan. 3, 1959 | Appointed, then elected |
| 86th-94th | Winston L. Prouty (R) | Jan. 3, 1959 | Sept. 10, 1971 | Died |
| 92nd-100th | Robert T. Stafford (R) | Sept. 16, 1971 | Jan. 3, 1989 | Appointed, then elected |
| 101st-109th | James M. Jeffords (R, I) | Jan. 3, 1989 | Jan. 3, 2007 | |
| 110th- | Bernard Sanders (I) | Jan. 3, 2007 | Present | |
| Class 3 | ||||
| 2nd-3rd | Stephen R. Bradley (ANTI-ADMIN) | Oct. 17, 1791 | Mar. 3, 1795 | |
| 4th-7th | Elijah Paine (F) | Mar. 4, 1795 | Sept. 1, 1801 | Resigned |
| 7th-12th | Stephen R. Bradley (R) | Oct. 15, 1801 | Mar. 3, 1813 | |
| 13th-15th | Dudley Chase (R) | Mar. 4, 1813 | Nov. 3, 1817 | Resigned |
| 15th | James Fisk (R) | Nov. 4, 1817 | Jan. 8, 1818 | Resigned |
| 15th-18th | William A. Palmer (R, ADAMS-CLAY R) | Oct. 20, 1818 | Mar. 3, 1825 | |
| 19th-21st | Dudley Chase (ADAMS, AJ) | Mar. 4, 1825 | Mar. 3, 1831 | |
| 22nd-27th | Samuel Prentiss (AJ, W) | Mar. 4, 1831 | Apr. 11, 1842 | Resigned |
| 27th | Samuel C. Crafts (W) | Apr. 23, 1842 | Mar. 3, 1843 | Appointed, then elected |
| 28th-32nd | William Upham (W) | Mar. 4, 1843 | Jan. 14, 1853 | Died |
| 32nd-33rd | Samuel S. Phelps1 (W) | Jan. 17, 1853 | Mar. 16, 1854 | Appointed |
| 33rd | Lawrence Brainerd (FS) | Oct. 14, 1854 | Mar. 3, 1855 | |
| 34th-39th | Jacob Collamer (OP, R) | Mar. 4, 1855 | Nov. 9, 1865 | Died |
| 39th | Luke P. Poland (R) | Nov. 21, 1865 | Mar. 3, 1867 | Appointed, then elected |
| 40th-55th | Justin S. Morrill (R) | Mar. 4, 1867 | Dec. 28, 1898 | Died |
| 55th-56th | Jonathan Ross (R) | Jan. 11, 1899 | Oct. 17, 1900 | Appointed |
| 56th-68th | William P. Dillingham (R) | Oct. 18, 1900 | Jul. 12, 1923 | Died |
| 68th-69th | Porter H. Dale (R) | Nov. 6, 19232 | Oct. 6, 1933 | Died |
| 73rd-76th | Ernest W. Gibson (R) | Nov. 21, 19333 | Jun. 20, 1940 | Appointed, then elected; died |
| 76th | Ernest W. Gibson Jr. (R) | Jun. 24, 1940 | Jan. 3, 1941 | Appointed |
| 77th-93rd | George D. Aiken (R) | Jan. 10, 19414 | Jan. 3, 1975 | |
| 94th-117th | Patrick J. Leahy (D) | Jan. 3, 1975 | Jan. 3, 2023 | |
| 118th- | Peter Welch (D) | Jan. 3, 2023 | Present | |
1. Appointed by governor, to fill vacancy. By resolution of Senate, Mar. 16, 1854, declared not entitled to retain his seat. Vacancy from Mar. 16 to Oct. 13, 1854.
2. Vacancy from July 13 to Nov. 5, 1923.
3. Vacancy from Oct. 7 to Nov. 20, 1933.
4. Elected Nov. 5, 1940, to fill vacancy in term ending Jan. 3, 1945. Took oath Jan. 10, 1941. Governor during interim.
