Iowa was admitted to the Union on December 28, 1846, and elects United States senators to class 2 and class 3. The state's current U.S. senators are Republicans Chuck Grassley (serving since 1981) and Joni Ernst (serving since 2015). Chuck Grassley is Iowa's longest-serving senator (since 1981).
Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | 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. | ||||||||||
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# | Senator | Party | Dates in office | Electoral history | T | T | Electoral history | Dates in office | Party | Senator | # | |
Vacant | Dec 28, 1846 – Dec 7, 1848 |
Legislature failed to elect.[1] | — | 29th | — | Legislature failed to elect.[1] | Dec 28, 1846 – Dec 7, 1848 |
Vacant | ||||
30th | ||||||||||||
1 | George W. Jones |
Democratic | Dec 7, 1848 – Mar 3, 1859 |
Elected in 1848. | 1 | 1 | Elected in 1848. | Dec 7, 1848 – Feb 22, 1855 |
Democratic | Augustus C. Dodge |
1 | |
31st | 2 | Re-elected in 1849.Resigned to become U.S. Minister to Spain, having lost re-election. | ||||||||||
32nd | ||||||||||||
Re-elected in 1852.Lost renomination. | 2 | 33rd | ||||||||||
Feb 22, 1855 – Mar 3, 1855 |
Vacant | |||||||||||
34th | 3 | Elected in 1855.Elected invalidated, as the Iowa Senate had not participated in it. | Mar 4, 1855 – Jan 5, 1857 |
Free Soil | James Harlan |
2 | ||||||
Jan 5, 1857 – Jan 29, 1857 |
Vacant | |||||||||||
Re-elected to finish his vacant term. | Jan 29, 1857 – May 15, 1865 |
Republican | James Harlan | |||||||||
35th | ||||||||||||
2 | James W. Grimes |
Republican | Mar 4, 1859 – Dec 6, 1869 |
Elected in 1858. | 3 | 36th | ||||||
37th | 4 | Re-elected in 1860.Resigned to become U.S. Secretary of the Interior. | ||||||||||
38th | ||||||||||||
Re-elected in 1864.Resigned due to ill health. | 4 | 39th | ||||||||||
May 15, 1865 – Jan 13, 1866 |
Vacant | |||||||||||
Elected to finish Harlan's term.[2]Lost nomination for the next term. | Jan 13, 1866 – Mar 3, 1867 |
Republican | Samuel J. Kirkwood |
3 | ||||||||
40th | 5 | Elected in 1866.[3]Lost re-election. | Mar 4, 1867 – Mar 3, 1873 |
Republican | James Harlan |
4 | ||||||
41st | ||||||||||||
Vacant | Dec 6, 1869 – Jan 18, 1870 |
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3 | James B. Howell |
Republican | Jan 18, 1870 – Mar 3, 1871 |
Elected to finish Grimes's term.Retired. | ||||||||
4 | George G. Wright |
Republican | Mar 4, 1871 – Mar 3, 1877 |
Elected in 1870.Retired. | 5 | 42nd | ||||||
43rd | 6 | Elected in 1872.[4] | Mar 4, 1873 – Aug 4, 1908 |
Republican | William B. Allison |
5 | ||||||
44th | ||||||||||||
5 | Samuel J. Kirkwood |
Republican | Mar 4, 1877 – Mar 7, 1881 |
Elected in 1876 or 1877.Resigned to become U.S. Secretary of the Interior. | 6 | 45th | ||||||
46th | 7 | Re-elected in 1878.[5] | ||||||||||
47th | ||||||||||||
6 | James W. McDill |
Republican | Mar 8, 1881 – Mar 3, 1883 |
Appointed to continue Kirkwood's term.Elected in 1882 to finish Kirkwood's term.[6]Retired. | ||||||||
7 | James F. Wilson |
Republican | Mar 4, 1883 – Mar 3, 1895 |
Elected in 1882.[7] | 7 | 48th | ||||||
49th | 8 | Re-elected in 1884.[8] | ||||||||||
50th | ||||||||||||
Re-elected in 1888.Retired. | 8 | 51st | ||||||||||
52nd | 9 | Re-elected in 1890.[9] | ||||||||||
53rd | ||||||||||||
8 | John H. Gear |
Republican | Mar 4, 1895 – Jul 14, 1900 |
Elected in 1894.[10]Re-elected in 1900,[11] but died. | 9 | 54th | ||||||
55th | 10 | Re-elected in 1896.[12] | ||||||||||
56th | ||||||||||||
Vacant | Jul 14, 1900 – Aug 22, 1900 |
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9 | Jonathan P. Dolliver |
Republican | Aug 22, 1900 – Oct 15, 1910 |
Appointed to finish Gear's term. | ||||||||
Appointed to begin the vacant term.Elected in 1902 to finish the vacant term.[13] | 10 | 57th | ||||||||||
58th | 11 | Re-elected in 1902.[14]Renominated in 1908 but died before the general election. | ||||||||||
59th | ||||||||||||
Re-elected in 1907.Died. | 11 | 60th | ||||||||||
Aug 4, 1908 – Nov 24, 1908 |
Vacant | |||||||||||
Elected to finish Allison's term. | Nov 24, 1908 – Jul 30, 1926 |
Republican | Albert B. Cummins |
6 | ||||||||
61st | 12 | Re-elected in 1909. | ||||||||||
Vacant | Oct 15, 1910 – Nov 12, 1910 |
|||||||||||
10 | Lafayette Young |
Republican | Nov 12, 1910 – Apr 11, 1911 |
Appointed to continue Dolliver's term.Lost election to finish Dolliver's term. | ||||||||
62nd | ||||||||||||
11 | William S. Kenyon |
Republican | Apr 12, 1911 – Feb 24, 1922 |
Elected to finish Dolliver's term. | ||||||||
Re-elected in 1913. | 12 | 63rd | ||||||||||
64th | 13 | Re-elected in 1914. | ||||||||||
65th | ||||||||||||
Re-elected in 1918.Resigned to become Judge of the U.S. Court of Appeals. | 13 | 66th | ||||||||||
67th | 14 | Re-elected in 1920.Lost renomination, then died. | ||||||||||
12 | Charles A. Rawson |
Republican | Feb 24, 1922 – Dec 1, 1922 |
Appointed to continue Kenyon's term.Retired when his successor was elected. | ||||||||
13 | Smith W. Brookhart |
Republican | Dec 1, 1922 – Apr 12, 1926 |
Elected to finish Kenyon's term. | ||||||||
68th | ||||||||||||
Re-elected in 1924.Lost election challenge. | 14 | 69th | ||||||||||
14 | Daniel F. Steck |
Democratic | Apr 12, 1926 – Mar 3, 1931 |
Successfully challenged his predecessor's election.Lost re-election. | ||||||||
Jul 30, 1926 – Aug 7, 1926 |
Vacant | |||||||||||
Appointed to continue Cummins's term.Elected in 1926 to finish Cummins's term.[15]Retired. | Aug 7, 1926 – Mar 3, 1927 |
Republican | David W. Stewart |
7 | ||||||||
70th | 15 | Elected in 1926.Lost renomination and then lost re-election as an Independent. | Mar 4, 1927 – Mar 3, 1933 |
Republican | Smith W. Brookhart |
8 | ||||||
71st | ||||||||||||
15 | L. J. Dickinson |
Republican | Mar 4, 1931 – Jan 3, 1937 |
Elected in 1930.Lost re-election. | 15 | 72nd | ||||||
73rd | 16 | Elected in 1932.Died. | Mar 4, 1933 – Jul 16, 1936 |
Democratic | Louis Murphy |
9 | ||||||
74th | ||||||||||||
Jul 16, 1936 – Nov 3, 1936 |
Vacant | |||||||||||
Elected to finish Murphy's term. | Nov 3, 1936 – Jan 3, 1945 |
Democratic | Guy Gillette |
10 | ||||||||
16 | Clyde L. Herring |
Democratic | Jan 3, 1937 – Jan 3, 1943 |
Elected in 1936. Did not take seat until Jan 15, 1937 in order to remain Governor of Iowa.Lost re-election. |
16 | 75th | ||||||
76th | 17 | Re-elected in 1938.Lost re-election. | ||||||||||
77th | ||||||||||||
17 | George A. Wilson |
Republican | Jan 3, 1943 – Jan 3, 1949 |
Elected in 1942. Did not take seat until Jan 14, 1943 in order to remain Governor of Iowa.Lost re-election. |
17 | 78th | ||||||
79th | 18 | Elected in 1944. | Jan 3, 1945 – Jan 3, 1969 |
Republican | Bourke B. Hickenlooper |
11 | ||||||
80th | ||||||||||||
18 | Guy Gillette |
Democratic | Jan 3, 1949 – Jan 3, 1955 |
Elected in 1948.Lost re-election. | 18 | 81st | ||||||
82nd | 19 | Re-elected in 1950. | ||||||||||
83rd | ||||||||||||
19 | Thomas E. Martin |
Republican | Jan 3, 1955 – Jan 3, 1961 |
Elected in 1954.Retired. | 19 | 84th | ||||||
85th | 20 | Re-elected in 1956. | ||||||||||
86th | ||||||||||||
20 | Jack Miller |
Republican | Jan 3, 1961 – Jan 3, 1973 |
Elected in 1960. | 20 | 87th | ||||||
88th | 21 | Re-elected in 1962Retired. | ||||||||||
89th | ||||||||||||
Re-elected in 1966.Lost re-election. | 21 | 90th | ||||||||||
91st | 22 | Elected in 1968.Retired. | Jan 3, 1969 – Jan 3, 1975 |
Democratic | Harold Hughes |
12 | ||||||
92nd | ||||||||||||
21 | Dick Clark |
Democratic | Jan 3, 1973 – Jan 3, 1979 |
Elected in 1972.Lost re-election. | 22 | 93rd | ||||||
94th | 23 | Elected in 1974.Lost re-election. | Jan 3, 1975 – Jan 3, 1981 |
Democratic | John Culver |
13 | ||||||
95th | ||||||||||||
22 | Roger Jepsen |
Republican | Jan 3, 1979 – Jan 3, 1985 |
Elected in 1978.Lost re-election. | 23 | 96th | ||||||
97th | 24 | Elected in 1980. | Jan 3, 1981 – present |
Republican | Chuck Grassley |
14 | ||||||
98th | ||||||||||||
23 | Tom Harkin |
Democratic | Jan 3, 1985 – Jan 3, 2015 |
Elected in 1984. | 24 | 99th | ||||||
100th | 25 | Re-elected in 1986. | ||||||||||
101st | ||||||||||||
Re-elected in 1990. | 25 | 102nd | ||||||||||
103rd | 26 | Re-elected in 1992. | ||||||||||
104th | ||||||||||||
Re-elected in 1996. | 26 | 105th | ||||||||||
106th | 27 | Re-elected in 1998. | ||||||||||
107th | ||||||||||||
Re-elected in 2002. | 27 | 108th | ||||||||||
109th | 28 | Re-elected in 2004. | ||||||||||
110th | ||||||||||||
Re-elected in 2008Retired. | 28 | 111th | ||||||||||
112th | 29 | Re-elected in 2010. | ||||||||||
113th | ||||||||||||
24 | Joni Ernst |
Republican | Jan 3, 2015 – present |
Elected in 2014. | 29 | 114th | ||||||
115th | 30 | Re-elected in 2016. | ||||||||||
116th | ||||||||||||
Re-elected in 2020. | 30 | 117th | ||||||||||
118th | 31 | Re-elected in 2022. | ||||||||||
119th | ||||||||||||
To be determined in the 2026 election. | 31 | 120th | ||||||||||
121st | 32 | To be determined in the 2028 election. | ||||||||||
# | Senator | Party | Years in office | Electoral history | T | C | T | Electoral history | Years in office | Party | Senator | # |
Class 2 | Class 3 |