| 1 | Alaska | Class 2 | 86th - 90th | E. L. (Bob) Bartlett (D) | Jan. 3, 1959 | Dec. 11, 1968 | Died |
| 2 | Alaska | Class 2 | 90th - 110th | Theodore F. (Ted) Stevens (R) | Dec. 24, 1968 | Jan. 3, 2009 | Appointed, then elected |
| 3 | Alaska | Class 2 | 111th - 113th | Mark Begich (D) | Jan. 3, 2009 | Jan. 3, 2015 | |
| 4 | Alaska | Class 2 | 114th - | Daniel Scott Sullivan (R) | Jan. 3, 2015 | Present | |
| 5 | Alaska | Class 3 | 86th - 90th | Ernest H. Gruening (D) | Jan. 3, 1959 | Jan. 3, 1969 | |
| 6 | Alaska | Class 3 | 91st - 96th | M. R. (Mike) Gravel (D) | Jan. 3, 1969 | Jan. 3, 1981 | |
| 7 | Alaska | Class 3 | 97th - 107th | Frank H. Murkowski (R) | Jan. 3, 1981 | Dec. 2, 2002 | Resigned |
| 8 | Alaska | Class 3 | 107th - | Lisa Murkowski (R) | Dec. 20, 2002 | Present | Appointed, then elected |
| 9 | Alabama | Class 2 | 16th - 28th | William R. King (R, JR, J, D) | Dec. 14, 1819 | Apr. 15, 1844 | Resigned |
| 10 | Alabama | Class 2 | 28th - 30th | Dixon H. Lewis (D) | Apr. 22, 1844 | Oct. 25, 1848 | Appointed, then elected died |
| 11 | Alabama | Class 2 | 30th - 31st | Benjamin Fitzpatrick (D) | Nov. 25, 1848 | Nov. 30, 1849 | Appointed |
| 12 | Alabama | Class 2 | 31st - 32nd | Jeremiah Clemens (D) | Nov. 30, 1849 | Mar. 3, 1853 | |
| 13 | Alabama | Class 2 | 33rd - 38th | Clement Claiborne Clay Jr. (D) | Mar. 4, 1853 | Jan. 21, 18611 | |
| 14 | Alabama | Class 2 | 40th - 41st | Willard Warner (R) | Jul. 23, 18682 | Mar. 3, 1871 | |
| 15 | Alabama | Class 2 | 42nd - 44th | George Goldthwaite (D) | Jan. 15, 18723 | Mar. 3, 1877 | |
| 16 | Alabama | Class 2 | 45th - 60th | John T. Morgan (D) | Mar. 4, 1877 | Jun. 11, 1907 | Died |
| 17 | Alabama | Class 2 | 60th - 66th | John H. Bankhead (D) | Jun. 18, 1907 | Mar. 1, 1920 | Appointed, then elected died |
| 18 | Alabama | Class 2 | 66th | Braxton B. Comer (D) | Mar. 5, 1920 | Nov. 2, 1920 | Appointed |
| 19 | Alabama | Class 2 | 66th - 71st | J. Thomas Heflin (D) | Nov. 3, 1920 | Mar. 3, 1931 | |
| 20 | Alabama | Class 2 | 72nd - 79th | John H. Bankhead II (D) | Mar. 4, 1931 | Jun. 12, 1946 | Died |
| 21 | Alabama | Class 2 | 79th | George R. Swift (D) | Jun. 15, 1946 | Nov. 5, 1946 | Appointed |
| 22 | Alabama | Class 2 | 79th - 95th | John J. Sparkman (D) | Nov. 6, 1946 | Jan. 3, 1979 | |
| 23 | Alabama | Class 2 | 96th - 104th | Howell T. Heflin (D) | Jan. 3, 1979 | Jan. 3, 1997 | |
| 24 | Alabama | Class 2 | 105th - | Jefferson B. Sessions III (R) | Jan. 3, 1997 | Present | |
| 25 | Alabama | Class 3 | 16th - 17th | John W. Walker (R) | Dec. 14, 1819 | Dec. 12, 1822 | Resigned |
| 26 | Alabama | Class 3 | 17th - 18th | William Kelly (R, JR) | Dec. 12, 1822 | Mar. 3, 1825 | |
| 27 | Alabama | Class 3 | 19th | Henry H. Chambers (J) | Mar. 4, 1825 | Jan. 24, 1826 | Died |
| 28 | Alabama | Class 3 | 19th | Israel Pickens (J) | Feb. 17, 1826 | Nov. 27, 1826 | Appointed |
| 29 | Alabama | Class 3 | 19th - 21st | John McKinley (J) | Nov. 27, 1826 | Mar. 3, 1831 | |
| 30 | Alabama | Class 3 | 22nd - 24th | Gabriel Moore (J, AJ) | Mar. 4, 1831 | Mar. 3, 1837 | |
| 31 | Alabama | Class 3 | 25th | John McKinley (D) | Mar. 4, 1837 | Apr. 22, 1837 | Resigned |
| 32 | Alabama | Class 3 | 25th - 27th | Clement Comer Clay (D) | Jun. 19, 1837 | Nov. 15, 1841 | Resigned |
| 33 | Alabama | Class 3 | 27th - 30th | Arthur P. Bagby (D) | Nov. 24, 1841 | Jun. 16, 1848 | Resigned |
| 34 | Alabama | Class 3 | 30th - 32nd | William R. King (D) | Jul. 1, 1848 | Dec. 20, 1852 | Appointed, then elected resigned |
| 35 | Alabama | Class 3 | 32nd - 36th | Benjamin Fitzpatrick (D) | Jan. 14, 1853 | Jan. 21, 18614 | Appointed, then elected withdrew |
| 36 | Alabama | Class 3 | 40th - 45th | George E. Spencer (R) | Jul. 21, 18685 | Mar. 3, 1879 | |
| 37 | Alabama | Class 3 | 46th | George S. Houston (D) | Mar. 4, 1879 | Dec. 31, 1879 | Died |
| 38 | Alabama | Class 3 | 46th | Luke Pryor (D) | Jan. 7, 1880 | Nov. 23, 1880 | Appointed |
| 39 | Alabama | Class 3 | 46th - 54th | James L. Pugh (D) | Nov. 24, 1880 | Mar. 3, 1897 | |
| 40 | Alabama | Class 3 | 55th - 60th | Edmund W. Pettus (D) | Mar. 4, 1897 | Jul. 27, 1907 | Died |
| 41 | Alabama | Class 3 | 60th - 63rd | Joseph F. Johnston (D) | Aug. 6, 1907 | Aug. 8, 1913 | Died |
| 42 | Alabama | Class 3 | 63rd | Francis S. White (D) | May 11, 19146 | Mar. 3, 1915 | |
| 43 | Alabama | Class 3 | 64th - 69th | Oscar W. Underwood (D) | Mar. 4, 1915 | Mar. 3, 1927 | |
| 44 | Alabama | Class 3 | 70th - 75th | Hugo L. Black (D) | Mar. 4, 1927 | Aug. 19, 1937 | Resigned |
| 45 | Alabama | Class 3 | 75th | Dixie Bibb Graves (D) | Aug. 20, 1937 | Jan. 10, 1938 | Appointed resigned |
| 46 | Alabama | Class 3 | 75th - 90th | J. Lister Hill (D) | Jan. 11, 1938 | Jan. 2, 1969 | Appointed, then elected |
| 47 | Alabama | Class 3 | 91st - 95th | James B. Allen (D) | Jan. 3, 1969 | Jun. 1, 1978 | Died |
| 48 | Alabama | Class 3 | 95th | Maryon Pittman Allen (D) | Jun. 8, 1978 | Nov. 7, 1978 | Appointed |
| 49 | Alabama | Class 3 | 95th - 96th | Donald W. Stewart (D) | Nov. 8, 1978 | Jan. 1, 1981 | Resigned |
| 50 | Alabama | Class 3 | 96th - 99th | Jeremiah A. Denton Jr. (R) | Jan. 2, 19817 | Jan. 3, 1987 | |
| 51 | Alabama | Class 3 | 100th - | Richard C. Shelby (D, R) | Jan. 3, 1987 | Present | |
| 52 | Arkansas | Class 2 | 24th - 28th | William S. Fulton (J, D) | Sept. 18, 1836 | Aug. 15, 1844 | Died |
| 53 | Arkansas | Class 2 | 28th - 30th | Chester Ashley (D) | Nov. 8, 1844 | Apr. 29, 1848 | Died |
| 54 | Arkansas | Class 2 | 30th - 37th | William K. Sebastian (D) | May 12, 1848 | Jul. 11, 1861 | Appointed, then elected Expelled |
| 55 | Arkansas | Class 2 | 40th - 41st | Alexander McDonald (R) | Jun. 22, 18681 | Mar. 3, 1871 | |
| 56 | Arkansas | Class 2 | 42nd - 44th | Powell Clayton (R) | Mar. 4, 1871 | Mar. 3, 1877 | |
| 57 | Arkansas | Class 2 | 45th - 49th | Augustus H. Garland (D) | Mar. 4, 1877 | Mar. 6, 1885 | Resigned |
| 58 | Arkansas | Class 2 | 49th - 59th | James H. Berry (D) | Mar. 20, 1885 | Mar. 3, 1907 | |
| 59 | Arkansas | Class 2 | 60th - 62nd | Jeff Davis (D) | Mar. 4, 1907 | Jan. 3, 1913 | Died |
| 60 | Arkansas | Class 2 | 62nd | John N. Heiskell (D) | Jan. 6, 1913 | Jan. 29, 1913 | Appointed |
| 61 | Arkansas | Class 2 | 62nd | William M. Kavanaugh (D) | Jan. 29, 1913 | Mar. 3, 1913 | |
| 62 | Arkansas | Class 2 | 63rd - 75th | Joseph T. Robinson (D) | Mar. 10, 19132 | Jul. 14, 1937 | Died |
| 63 | Arkansas | Class 2 | 75th - 77th | John E. Miller (D) | Nov. 15, 19373 | Mar. 31, 1941 | Resigned |
| 64 | Arkansas | Class 2 | 77th | G. Lloyd Spencer (D) | Apr. 1, 1941 | Jan. 3, 1943 | Appointed |
| 65 | Arkansas | Class 2 | 78th - 95th | John L. McCellan (D) | Jan. 3, 1943 | Nov. 28, 1977 | Died |
| 66 | Arkansas | Class 2 | 95th | Kaneaster Hodges Jr. (D) | Dec. 10, 1977 | Jan. 3, 1979 | Appointed |
| 67 | Arkansas | Class 2 | 96th - 104th | David H. Pryor (D) | Jan. 3, 1979 | Jan. 3, 1997 | |
| 68 | Arkansas | Class 2 | 105th - 107th | Tim Hutchinson (R) | Jan. 3, 1997 | Jan. 3, 2003 | |
| 69 | Arkansas | Class 2 | 108th - 113th | Mark Pryor (D) | Jan. 3, 2003 | Jan. 3, 2015 | |
| 70 | Arkansas | Class 2 | 114th - | Tom Cotton (R) | Jan. 3, 2015 | Present | |
| 71 | Arkansas | Class 3 | 24th - 30th | Ambrose H. Sevier (J, D) | Sept. 18, 1836 | Mar. 15, 1848 | Resigned |
| 72 | Arkansas | Class 3 | 30th - 33rd | Solon Borland (D) | Mar. 30, 1848 | Apr. 3, 1853 | Appointed, then elected resigned |
| 73 | Arkansas | Class 3 | 33rd - 36th | Robert W. Johnson (D) | Jul. 6, 1853 | Mar. 3, 1861 | Appointed, then elected |
| 74 | Arkansas | Class 3 | 37th | Charles B. Mitchel (D) | Mar. 4, 1861 | Jul. 11, 1861 | Expelled |
| 75 | Arkansas | Class 3 | 40th - 42nd | Benjamin F. Rice (R) | Jun. 23, 18684 | Mar. 3, 1873 | |
| 76 | Arkansas | Class 3 | 43rd - 45th | Stephen W. Dorsey (R) | Mar. 4, 1873 | Mar. 3, 1879 | |
| 77 | Arkansas | Class 3 | 46th - 48th | James D. Walker (D) | Mar. 4, 1879 | Mar. 3, 1885 | |
| 78 | Arkansas | Class 3 | 49th - 57th | James K. Jones (D) | Mar. 4, 1885 | Mar. 3, 1903 | |
| 79 | Arkansas | Class 3 | 58th - 64th | James P. Clarke (D) | Mar. 4, 1903 | Oct. 1, 1916 | Died |
| 80 | Arkansas | Class 3 | 64th - 66th | William F. Kirby (D) | Nov. 8, 1916 | Mar. 3, 1921 | |
| 81 | Arkansas | Class 3 | 67th - 72nd | Thaddeus H. Carraway (D) | Mar. 4, 1921 | Nov. 6, 1931 | Died |
| 82 | Arkansas | Class 3 | 72nd - 78th | Hattie W. Carraway (D) | Nov. 13, 1931 | Jan. 3, 1945 | Appointed, then elected |
| 83 | Arkansas | Class 3 | 79th - 93rd | J. William Fulbright (D) | Jan. 3, 1945 | Dec. 31, 1974 | Resigned |
| 84 | Arkansas | Class 3 | 94th - 105th | Dale Bumpers (D) | Jan. 3, 1975 | Jan. 3, 1999 | |
| 85 | Arkansas | Class 3 | 106th - 111th | Blanche Lambert Lincoln (D) | Jan. 3, 1999 | Jan. 3, 2011 | |
| 86 | Arkansas | Class 3 | 112th - | John Boozman (R) | Jan. 3, 2011 | Present | |
| 87 | Arizona | Class 1 | 62nd - 76th | Henry Fountain Ashurst (D) | Mar. 27, 1912 | Jan. 3, 1941 | |
| 88 | Arizona | Class 1 | 77th - 82nd | Ernest W. McFarland (D) | Jan. 3, 1941 | Jan. 3, 1953 | |
| 89 | Arizona | Class 1 | 83rd - 88th | Barry M. Goldwater (R) | Jan. 3, 1953 | Jan. 3, 1965 | |
| 90 | Arizona | Class 1 | 89th - 94th | Paul J. Fannin (R) | Jan. 3, 1965 | Jan. 3, 1977 | |
| 91 | Arizona | Class 1 | 95th - 103rd | Dennis W. DeConcini (D) | Jan. 3, 1977 | Jan. 3, 1995 | |
| 92 | Arizona | Class 1 | 104th - 112th | Jon L. Kyl (R) | Jan. 3, 1995 | Jan. 3, 2013 | |
| 93 | Arizona | Class 1 | 113th - | Jeff Flake (R) | Jan. 3, 2013 | Present | |
| 94 | Arizona | Class 3 | 62nd - 66th | Marcus A. Smith (D) | Mar. 27, 1912 | Mar. 3, 1921 | |
| 95 | Arizona | Class 3 | 67th - 69th | Ralph H. Cameron (R) | Mar. 4, 1921 | Mar. 3, 1927 | |
| 96 | Arizona | Class 3 | 70th - 90th | Carl T. Hayden (D) | Mar. 4, 1927 | Jan. 3, 1969 | |
| 97 | Arizona | Class 3 | 91st - 99th | Barry M. Goldwater (R) | Jan. 3, 1969 | Jan. 3, 1987 | |
| 98 | Arizona | Class 3 | 100th - | John S. McCain III (R) | Jan. 3, 1987 | Present | |
| 99 | California | Class 1 | 31st | John C. Fremont (D) | Sept. 9, 1850 | Mar. 3, 1851 | |
| 100 | California | Class 1 | 32nd - 34th | John B. Weller (D) | Jan. 30, 1852 | Mar. 3, 1857 | |