| Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2006, 2012, 2018, and 2024. The next election will be in 2030. |
C |
Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. |
| # |
Senator |
Party |
Dates in office |
Electoral history |
T |
T |
Electoral history |
Dates in office |
Party |
Senator |
# |
| Vacant |
May 29, 1848 – Jun 8, 1848 |
Wisconsin elected its senators 10 days after statehood. |
1 |
30th |
1 |
Wisconsin elected its senators 10 days after statehood. |
May 29, 1848 – Jun 8, 1848 |
Vacant |
| 1 |
 Henry Dodge |
Democratic |
Jun 8, 1848 – Mar 3, 1857 |
Elected in 1848. |
Elected in 1848. |
Jun 8, 1848 – Mar 3, 1855 |
Democratic |
 Isaac P. Walker |
1 |
| 31st |
2 |
Re-elected in 1849.Retired. |
| Re-elected in 1851.Retired. |
2 |
32nd |
| 33rd |
| 34th |
3 |
Elected in 1855. Retired. |
Mar 4, 1855 – Mar 3, 1861 |
Republican |
 Charles Durkee |
2 |
| 2 |
 James R. Doolittle |
Republican |
Mar 4, 1857 – Mar 3, 1869 |
Elected in 1857. |
3 |
35th |
| 36th |
| 37th |
4 |
Elected in 1861. |
Mar 4, 1861 – Mar 3, 1879 |
Republican |
 Timothy O. Howe |
3 |
Re-elected in 1863. Retired. |
4 |
38th |
| 39th |
| 40th |
5 |
Re-elected in 1867. |
| 3 |
 Matthew H. Carpenter |
Republican |
Mar 4, 1869 – Mar 3, 1875 |
Elected in 1869.Lost re-election. |
5 |
41st |
| 42nd |
| 43rd |
6 |
Re-elected in 1872.Lost re-election. |
| 4 |
 Angus Cameron |
Republican |
Mar 4, 1875 – Mar 3, 1881 |
Elected in 1875.Retired. |
6 |
44th |
| 45th |
| 46th |
7 |
Elected in 1879.Died. |
Mar 4, 1879 – Feb 24, 1881 |
Republican |
 Matthew H. Carpenter |
4 |
| |
Feb 24, 1881 – Mar 14, 1881 |
Vacant |
| 5 |
 Philetus Sawyer |
Republican |
Mar 4, 1881 – Mar 3, 1893 |
Elected in 1881. |
7 |
47th |
| Elected to finish Carpenter's term.Retired. |
Mar 14, 1881 – Mar 3, 1885 |
Republican |
 Angus Cameron |
5 |
| 48th |
| 49th |
8 |
Elected in 1885.Lost re-election. |
Mar 4, 1885 – Mar 3, 1891 |
Republican |
 John Coit Spooner |
6 |
| Re-elected in 1887.Retired. |
8 |
50th |
| 51st |
| 52nd |
9 |
Elected in 1891.Lost renomination. |
Mar 4, 1891 – Mar 3, 1897 |
Democratic |
 William F. Vilas |
7 |
| 6 |
 John L. Mitchell |
Democratic |
Mar 4, 1893 – Mar 3, 1899 |
Elected in 1893.Retired. |
9 |
53rd |
| 54th |
| 55th |
10 |
Elected in 1897.[2] |
Mar 4, 1897 – Apr 30, 1907 |
Republican |
 John Coit Spooner |
8 |
| 7 |
 Joseph V. Quarles |
Republican |
Mar 4, 1899 – Mar 3, 1905 |
Elected in 1899.Retired. |
10 |
56th |
| 57th |
| 58th |
11 |
Re-elected in 1903.[3]Resigned. |
| 8 |
 Robert M. La Follette |
Republican |
Jan 4, 1906 – Jun 18, 1925 |
Elected in 1905.Did not assume office until Jan 4, 1906 after resigning as Governor of Wisconsin. |
11 |
59th |
| 60th |
| |
Apr 30, 1907 – May 17, 1907 |
Vacant |
| Elected to finish Spooner's term. |
May 17, 1907 – Mar 3, 1915 |
Republican |
 Isaac Stephenson |
9 |
| 61st |
12 |
Re-elected in 1909.Retired. |
| Re-elected in 1911. |
12 |
62nd |
| 63rd |
| 64th |
13 |
Elected in 1914.Died. |
Mar 4, 1915 – Oct 21, 1917 |
Democratic |
 Paul O. Husting |
10 |
| Re-elected in 1916. |
13 |
65th |
| |
Oct 21, 1917 – Apr 18, 1918 |
Vacant |
| Elected in 1918 to finish Husting's term. |
Apr 18, 1918 – Mar 3, 1927 |
Republican |
 Irvine Lenroot |
11 |
| 66th |
| 67th |
14 |
Re-elected in 1920.Lost renomination. |
| Re-elected in 1922.Died. |
14 |
68th |
| 69th |
| Vacant |
Jun 18, 1925 – Sep 30, 1925 |
|
| 9 |
 Robert M. La Follette Jr. |
Republican |
Sep 30, 1925 – Jan 3, 1947 |
Elected to finish his father's term |
| 70th |
15 |
Elected in 1926.Lost renomination. |
Mar 4, 1927 – Mar 3, 1933 |
Republican |
 John J. Blaine |
12 |
| Re-elected in 1928. |
15 |
71st |
| 72nd |
| 73rd |
16 |
Elected in 1932.Lost re-election. |
Mar 4, 1933 – Jan 3, 1939 |
Democratic |
 F. Ryan Duffy |
13 |
| Progressive |
Re-elected in 1934. |
16 |
74th |
| 75th |
| 76th |
17 |
Elected in 1938. |
Jan 3, 1939 – Jan 3, 1963 |
Republican |
 Alexander Wiley |
14 |
| Re-elected in 1940.Lost nomination as a Republican. |
17 |
77th |
| 78th |
| 79th |
18 |
Re-elected in 1944. |
| 10 |
 Joseph McCarthy |
Republican |
Jan 3, 1947 – May 2, 1957 |
Elected in 1946. |
18 |
80th |
| 81st |
| 82nd |
19 |
Re-elected in 1950. |
| Re-elected in 1952.Died. |
19 |
83rd |
| 84th |
| 85th |
20 |
Re-elected in 1956.Lost re-election. |
| Vacant |
May 2, 1957 – Aug 27, 1957 |
|
| 11 |
 William Proxmire |
Democratic |
Aug 28, 1957 – Jan 3, 1989 |
Elected to finish McCarthy's term |
| Re-elected in 1958. |
20 |
86th |
| 87th |
| 88th |
21 |
Elected in 1962. |
Jan 3, 1963 – Jan 3, 1981 |
Democratic |
 Gaylord Nelson |
15 |
| Re-elected in 1964. |
21 |
89th |
| 90th |
| 91st |
22 |
Re-elected in 1968. |
| Re-elected in 1970. |
22 |
92nd |
| 93rd |
| 94th |
23 |
Re-elected in 1974.Lost re-election. |
| Re-elected in 1976. |
23 |
95th |
| 96th |
| 97th |
24 |
Elected in 1980. |
Jan 3, 1981 – Jan 3, 1993 |
Republican |
 Bob Kasten |
16 |
| Re-elected in 1982.Retired. |
24 |
98th |
| 99th |
| 100th |
25 |
Re-elected in 1986.Lost re-election. |
| 12 |
 Herb Kohl |
Democratic |
Jan 3, 1989 – Jan 3, 2013 |
Elected in 1988. |
25 |
101st |
| 102nd |
| 103rd |
26 |
Elected in 1992. |
Jan 3, 1993 – Jan 3, 2011 |
Democratic |
 Russ Feingold |
17 |
| Re-elected in 1994. |
26 |
104th |
| 105th |
| 106th |
27 |
Re-elected in 1998. |
| Re-elected in 2000. |
27 |
107th |
| 108th |
| 109th |
28 |
Re-elected in 2004.Lost re-election. |
| Re-elected in 2006.Retired. |
28 |
110th |
| 111th |
| 112th |
29 |
Elected in 2010. |
Jan 3, 2011 – present |
Republican |
 Ron Johnson |
18 |
| 13 |
 Tammy Baldwin |
Democratic |
Jan 3, 2013 – present |
Elected in 2012. |
29 |
113th |
| 114th |
| 115th |
30 |
Re-elected in 2016. |
| Re-elected in 2018. |
30 |
116th |
| 117th |
| 118th |
31 |
Re-elected in 2022. |
| Re-elected in 2024. |
31 |
119th |
| 120th |
| 121st |
32 |
To be determined in the 2028 election. |
| To be determined in the 2030 election. |
32 |
122nd |
| # |
Senator |
Party |
Years in office |
Electoral history |
T |
C |
T |
Electoral history |
Years in office |
Party |
Senator |
# |
| Class 1 |
Class 3 |