| CONGRESS | SENATOR | TERM BEGAN | TERM ENDED | COMMENTS |
| Class 1 |
| 51st-52nd | John B. Allen (R) |
Nov.
20, 1889 |
Mar.
3, 1893 | |
| 53rd-55th | John L. Wilson (R) |
Feb.
19, 1895 |
Mar.
3, 1899 | |
| 56th-58th | Addison G. Foster (R) |
Mar.
4, 1899 |
Mar.
3, 1905 | |
| 59th-61st | Samuel H. Piles (R) |
Mar.
4, 1905 |
Mar.
3, 1911 | |
| 62nd-67th | Miles Poindexter (R, PR, R) |
Mar.
4, 1911 |
Mar.
3, 1923 | |
| 68th-73rd | Clarence C. Dill (D) |
Mar.
4, 1923 | Jan. 3, 1935 | |
| 74th-76th | Lewis B. Schwellenbach (D) | Jan. 3, 1935 |
Dec.
16, 1940 | Resigned |
| 76th-79th | Monrad C. Wallgren (D) |
Dec.
19, 1940 | Jan. 9, 1945 | Resigned |
| 79th | Hugh B. Mitchell (D) | Jan. 10, 1945 |
Dec.
25, 1946 | Appointed; resigned |
| 79th-82nd | Harry P. Cain (R) |
Dec.
26, 1946 | Jan. 3, 1953 | |
| 83rd-98th | Henry M. (Scoop) Jackson (D) | Jan. 3, 1953 |
Sept.
1, 1983 | Died |
| 98th-100th | Daniel J. Evans (R) |
Sept.
8, 1983 | Jan. 3, 1989 | Appointed, then elected |
| 101st-106th | T. Slade Gorton III (R) | Jan. 3, 1989 | Jan. 3, 2001 | |
| 107th- | Maria E. Cantwell (D) | Jan. 3, 2001 |
Present
| |
| Class 3 |
| 51st-54th | Watson C. Squire (R) |
Nov.
20, 1889 |
Mar.
3, 1897 | |
| 55th-57th | George Turner (SR, D) |
Mar.
4, 1897 |
Mar.
3, 1903 | |
| 58th-60th | Levi Ankeny (R) |
Mar.
4, 1903 |
Mar.
3, 1909 | |
| 61st-72nd | Wesley L. Jones (R) |
Mar.
4, 1909 |
Nov.
19, 1932 | Died |
| 72nd | Elijah S. Grammer (R) |
Nov.
22, 1932 |
Mar.
3, 1933 | Appointed |
| 73rd-78th | Homer T. Bone (D) |
Mar.
4, 1933 |
Nov.
13, 1944 | Resigned |
| 78th-96th | Warren G. Magnuson (D) |
Dec.
14, 1944 | Jan. 3, 1981 | |
| 97th-99th | T. Slade Gorton III (R) | Jan. 3, 1981 | Jan. 3, 1987 | |
| 100th-102nd | Brockman Adams (D) | Jan. 3, 1987 | Jan. 3, 1993 | |
| 103rd- | Patty Murray (D) | Jan. 3, 1993 |
Present
| |
