| CONGRESS | NAME OF SENATOR | TERM BEGAN | TERM ENDED | COMMENTS |
|---|---|---|---|---|
| Class 1 | ||||
| 35th | Delazon Smith (D) | Feb. 14, 1859 | Mar. 3, 1859 | |
| 36th - 37th | Edward D. Baker (R) | Oct. 2, 1860 | Oct. 21, 1861 | Died |
| 37th | Benjamin Stark (D) | Oct. 29, 1861 | Sept. 12, 1862 | Appointed |
| 37th - 38th | Benjamin F. Harding (D) | Sept. 12, 1862 | Mar. 3, 1865 | |
| 39th - 41st | George Henry Williams (R) | Mar. 4, 1865 | Mar. 3, 1871 | |
| 42nd - 44th | James K. Kelly (D) | Mar. 4, 1871 | Mar. 3, 1877 | |
| 45th - 47th | La Fayette Grover (D) | Mar. 4, 1877 | Mar. 3, 1883 | |
| 48th - 53rd | Joseph N. Dolph (R) | Mar. 4, 1883 | Mar. 3, 1895 | |
| 54th - 56th | George W. McBride (R) | Mar. 4, 1895 | Mar. 3, 1901 | |
| 57th - 59th | John H. Mitchell (R) | Mar. 4, 1901 | Dec. 8, 1905 | Died |
| 59th | John M. Gearin (D) | Dec. 13, 1905 | Jan. 23, 1907 | Appointed |
| 59th | Frederick W. Mulkey (R) | Jan. 23, 1907 | Mar. 3, 1907 | |
| 60th - 62nd | Jonathan Bourne Jr. (R) | Mar. 4, 1907 | Mar. 3, 1913 | |
| 63rd - 65th | Harry Lane (D) | Mar. 4, 1913 | May 23, 1917 | Died |
| 65th | Charles L. McNary (R) | May 29, 1917 | Nov. 5, 1918 | Appointed |
| 65th | Frederick W. Mulkey (R) | Nov. 6, 1918 | Dec. 17, 1918 | Resigned |
| 65th - 78th | Charles L. McNary (R) | Dec. 18, 19181 | Feb. 25, 1944 | Died |
| 78th - 83rd | Guy Cordon (R) | Mar. 4, 1944 | Jan. 3, 1955 | Appointed, then elected |
| 84th - 86th | Richard L. Neuberger (D) | Jan. 3, 1955 | Mar. 9, 1960 | Died |
| 86th | Hall S. Lusk (D) | Mar. 16, 1960 | Nov. 8, 1960 | Appointed |
| 86th - 89th | Maurine B. Neuberger (D) | Nov. 9, 1960 | Jan. 3, 1967 | |
| 90th - 104th | Mark O. Hatfield (R) | Jan. 10, 19672 | Jan. 3, 1997 | |
| 105th - 110th | Gordon H. Smith (R) | Jan. 3, 1997 | Jan. 3, 2009 | |
| 111th - | Jeff Merkley (D) | Jan. 3, 2009 | Present | |
| Class 3 | ||||
| 35th - 36th | Joseph Lane (D) | Feb. 14, 1859 | Mar. 3, 1961 | |
| 37th - 39th | James W. Nesmith (D) | Mar. 4, 1861 | Mar. 3, 1867 | |
| 40th - 42nd | Henry W. Corbett (R) | Mar. 4, 1867 | Mar. 3, 1873 | |
| 43rd - 45th | John H. Mitchell (R) | Mar. 4, 1873 | Mar. 3, 1879 | |
| 46th - 48th | James H. Slater (D) | Mar. 4, 1879 | Mar. 3, 1885 | |
| 49th - 54th | John H. Mitchell (R) | Dec. 17, 18853 | Mar. 3, 1897 | |
| 55th - 57th | Joseph Simon (R) | Oct. 8, 18984 | Mar. 3, 1903 | |
| 58th - 60th | Charles W. Fulton (R) | Mar. 4, 1903 | Mar. 3, 1909 | |
| 61st - 66th | George E. Chamberlain (D) | Mar. 4, 1909 | Mar. 3, 1921 | |
| 67th - 69th | Robert N. Standfield (R) | Mar. 4, 1921 | Mar. 3, 1927 | |
| 70th - 75th | Frederick Steiwer (R) | Mar. 4, 1927 | Jan. 31, 1938 | Resigned |
| 75th | Alfred Evan Reames (D) | Feb. 1, 1938 | Nov. 8, 1938 | Appointed |
| 75th | Alexander G. Barry (R) | Nov. 9, 1938 | Jan. 3, 1939 | |
| 76th - 78th | Rufus C. Holman (R) | Jan. 3, 1939 | Jan. 3, 1945 | |
| 79th - 90th | Wayne L. Morse (R, I, D) | Jan. 3, 1945 | Jan. 3, 1969 | |
| 91st - 104th | Robert W. Packwood (R) | Jan. 3, 1969 | Oct. 1, 1995 | Resigned |
| 104th - | Ronald L. Wyden (D) | Feb. 5, 1996 | Present | |
1. Elected for the term beginning on Mar. 4, 1919, subsequently appointed to the remainder of the term expiring on Mar. 3, 1919.
2. Elected for the term beginning on Jan. 3, 1967, but continued to serve as governor during interim.
3. Elected on Nov. 18, 1885 for the term beginning on Mar. 4, 1885. Seat vacant from Mar. 4, 1885 to Dec. 16, 1885.
4. Elected on Oct. 8, 1898 for the term beginning on Mar. 4, 1897. Seat vacant from Mar. 4, 1897 to Oct. 7, 1898.
