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United States · Election results history · 2010 Senate · Iowa
Election 2010 Results

Each election opens in its own mode: the forecast before the votes are counted, the live count while races are still too close to call, and the results once every race is decided.

2010 US Senate election in Iowa

Chuck Grassley (Republican) beat Roxanne Conlin (Democrat) in Iowa in 2010, 64.4% to 33.3%, a margin of 31.0 points and 346,529 votes.

The Republican hold continued from 2004, when Charles E. Grassley also won.

Republicans led in 98 of the 99 counties and Democrats in 1. The largest, Polk, cast 160,582 votes and went to the Republican by 21.8 points. The closest was Jefferson, where 442 votes separated the two parties.

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Early projection, based on early and incomplete polling: the likely matchups, each weighted by the betting markets' odds of both nominations, not a result. Each county is its 2024 presidential margin moved by its state's projected swing; set a national vote and every state, district and county moves by the same amount from our projection. Colours run in 100 steps from a safe Republican to a safe Democratic margin. Boundaries: US Census Bureau.

Senate

CandidatePartyVotesShare
Chuck Grassley won Republican 718,215 64.4%
Roxanne Conlin Democratic 371,686 33.3%
All other candidates 26,162 2.3%
Total1,116,063

Every county

CountyDemocratRepublicanOthersTotalMargin
Polk 61,170 38.1% 96,219 59.9% 3,193 160,582 R+21.8
Linn 29,764 37.2% 48,488 60.5% 1,830 80,082 R+23.4
Scott 21,592 38.4% 33,050 58.7% 1,616 56,258 R+20.4
Johnson 26,047 50.4% 24,347 47.1% 1,262 51,656 D+3.3
Black Hawk 17,114 38.0% 27,099 60.2% 800 45,013 R+22.2
Dubuque 12,941 38.7% 19,634 58.7% 895 33,470 R+20.0
Story 12,029 37.3% 19,430 60.2% 819 32,278 R+22.9
Woodbury 9,461 30.5% 20,895 67.4% 647 31,003 R+36.9
Pottawattamie 7,907 29.8% 17,916 67.5% 711 26,534 R+37.7
Dallas 6,736 26.4% 18,126 71.2% 611 25,473 R+44.7
Warren 6,429 31.9% 13,273 65.9% 450 20,152 R+34.0
Cerro Gordo 6,440 37.4% 10,421 60.5% 366 17,227 R+23.1
Clinton 6,600 38.4% 10,189 59.2% 419 17,208 R+20.9
Jasper 5,031 33.6% 9,614 64.2% 322 14,967 R+30.6
Des Moines 6,365 42.8% 8,083 54.4% 410 14,858 R+11.6
Marshall 4,836 34.0% 9,026 63.5% 353 14,215 R+29.5
Muscatine 4,872 36.8% 7,974 60.3% 383 13,229 R+23.4
Webster 4,355 33.2% 8,533 65.1% 224 13,112 R+31.9
Marion 3,409 26.2% 9,326 71.5% 301 13,036 R+45.4
Sioux 973 7.6% 11,677 91.3% 135 12,785 R+83.7
Lee 5,276 44.9% 6,050 51.5% 432 11,758 R+6.6
Wapello 5,006 42.9% 6,308 54.0% 362 11,676 R+11.2
Boone 3,457 32.2% 7,014 65.4% 249 10,720 R+33.2
Benton 2,796 28.0% 6,936 69.5% 249 9,981 R+41.5
Bremer 2,815 28.7% 6,811 69.3% 196 9,822 R+40.7
Plymouth 1,422 16.2% 7,219 82.1% 150 8,791 R+65.9
Washington 2,280 26.3% 6,152 71.0% 235 8,667 R+44.7
Mahaska 1,866 22.2% 6,376 75.8% 170 8,412 R+53.6
Carroll 2,312 28.2% 5,731 69.8% 167 8,210 R+41.6
Winneshiek 2,766 33.9% 5,179 63.5% 209 8,154 R+29.6
Fayette 2,466 31.2% 5,265 66.7% 162 7,893 R+35.5
Buchanan 2,446 31.0% 5,291 67.1% 153 7,890 R+36.1
Jones 2,268 29.4% 5,236 67.9% 206 7,710 R+38.5
Poweshiek 2,746 36.7% 4,594 61.5% 134 7,474 R+24.7
Jackson 2,605 35.2% 4,561 61.7% 226 7,392 R+26.5
Dickinson 1,887 26.1% 5,191 71.9% 146 7,224 R+45.7
Cedar 2,148 30.6% 4,660 66.4% 209 7,017 R+35.8
Delaware 1,734 24.9% 5,048 72.5% 185 6,967 R+47.6
Clayton 2,106 30.3% 4,632 66.6% 213 6,951 R+36.3
Henry 1,916 28.1% 4,723 69.3% 172 6,811 R+41.2
Kossuth 1,928 28.6% 4,688 69.4% 137 6,753 R+40.9
Madison 1,810 26.8% 4,753 70.5% 180 6,743 R+43.6
Jefferson 2,987 44.9% 3,429 51.5% 242 6,658 R+6.6
Hardin 1,748 26.3% 4,760 71.7% 130 6,638 R+45.4
Iowa 1,673 25.6% 4,673 71.6% 184 6,530 R+45.9
Tama 2,023 31.1% 4,323 66.5% 150 6,496 R+35.4
Hamilton 1,856 29.9% 4,226 68.1% 123 6,205 R+38.2
Floyd 2,126 35.1% 3,793 62.6% 140 6,059 R+27.5
Clay 1,369 23.7% 4,254 73.7% 148 5,771 R+50.0
Butler 1,258 22.1% 4,339 76.1% 107 5,704 R+54.0
Buena Vista 1,239 22.2% 4,237 75.8% 114 5,590 R+53.6
O'Brien 831 15.2% 4,556 83.1% 94 5,481 R+68.0
Grundy 990 18.7% 4,191 79.2% 108 5,289 R+60.5
Allamakee 1,416 26.9% 3,584 68.1% 260 5,260 R+41.2
Harrison 1,240 23.6% 3,874 73.7% 141 5,255 R+50.1
Cass 1,154 22.2% 3,930 75.6% 112 5,196 R+53.4
Crawford 1,201 23.7% 3,749 73.8% 128 5,078 R+50.2
Lyon 620 12.4% 4,269 85.5% 106 4,995 R+73.1
Chickasaw 1,508 30.5% 3,331 67.4% 100 4,939 R+36.9
Wright 1,260 25.8% 3,554 72.7% 75 4,889 R+46.9
Mills 1,068 22.1% 3,633 75.3% 122 4,823 R+53.2
Page 945 19.7% 3,751 78.1% 105 4,801 R+58.4
Union 1,401 29.4% 3,257 68.3% 113 4,771 R+38.9
Cherokee 1,001 21.2% 3,632 76.9% 91 4,724 R+55.7
Hancock 1,144 24.7% 3,384 73.0% 109 4,637 R+48.3
Appanoose 1,398 30.4% 3,050 66.3% 149 4,597 R+35.9
Guthrie 1,238 27.1% 3,181 69.7% 147 4,566 R+42.6
Mitchell 1,274 28.4% 3,121 69.6% 90 4,485 R+41.2
Winnebago 1,236 28.2% 3,062 69.8% 91 4,389 R+41.6
Shelby 885 21.3% 3,166 76.3% 96 4,147 R+55.0
Calhoun 964 24.1% 2,971 74.2% 71 4,006 R+50.1
Sac 815 20.7% 3,035 77.2% 82 3,932 R+56.5
Humboldt 869 22.2% 2,966 75.6% 87 3,922 R+53.5
Palo Alto 1,139 29.3% 2,653 68.3% 93 3,885 R+39.0
Keokuk 915 23.7% 2,832 73.3% 116 3,863 R+49.6
Franklin 891 23.2% 2,859 74.6% 83 3,833 R+51.3
Greene 1,073 28.4% 2,610 69.2% 90 3,773 R+40.7
Clarke 1,041 28.2% 2,551 69.1% 101 3,693 R+40.9
Montgomery 722 19.8% 2,824 77.5% 98 3,644 R+57.7
Emmet 1,050 29.7% 2,419 68.4% 69 3,538 R+38.7
Lucas 967 27.3% 2,470 69.8% 101 3,538 R+42.5
Monona 881 25.0% 2,578 73.3% 60 3,519 R+48.2
Howard 1,154 34.1% 2,165 63.9% 69 3,388 R+29.8
Louisa 859 25.5% 2,411 71.6% 96 3,366 R+46.1
Worth 1,067 33.4% 2,046 64.1% 80 3,193 R+30.7
Davis 907 29.5% 2,042 66.3% 130 3,079 R+36.9
Adair 778 25.4% 2,220 72.5% 63 3,061 R+47.1
Pocahontas 654 21.7% 2,296 76.1% 68 3,018 R+54.4
Monroe 827 28.7% 1,983 68.8% 72 2,882 R+40.1
Decatur 846 29.4% 1,937 67.4% 92 2,875 R+37.9
Van Buren 807 28.4% 1,916 67.4% 118 2,841 R+39.0
Audubon 747 27.5% 1,908 70.3% 59 2,714 R+42.8
Ida 422 15.8% 2,194 82.2% 53 2,669 R+66.4
Fremont 595 22.7% 1,949 74.4% 77 2,621 R+51.7
Taylor 581 23.2% 1,866 74.5% 57 2,504 R+51.3
Osceola 323 13.4% 2,013 83.7% 68 2,404 R+70.3
Wayne 582 25.2% 1,683 72.8% 48 2,313 R+47.6
Ringgold 552 25.9% 1,537 72.0% 46 2,135 R+46.1
Adams 442 25.6% 1,234 71.5% 51 1,727 R+45.9

Margin: the Democrat's share of all votes minus the Republican's. Sources and how the results were checked.

Iowa Senate elections we hold

YearWinnerMargin
2022 Chuck Grassley (R) R+12.2
2020 Joni Ernst (R) R+6.6
2016 Chuck Grassley (R) R+24.4
2014 Joni Ernst (R) R+8.3
2010 Chuck Grassley (R) R+31.0
2008 Tom Harkin (D) D+25.4
2004 Charles E. Grassley (R) R+42.3
2002 Tom Harkin (D) D+10.4
1998 Charles E. Grassley (R) R+37.9
1996 Tom Harkin (D) D+5.1
1992 Chuck Grassley (R) R+42.4
1990 Tom Harkin (D) D+9.1
1986 Charles E. Grassley (R) R+32.5
1984 Tom Harkin (D) D+11.8
1980 Charles E. Grassley (R) R+7.9
1978 Roger W. Jepsen (R) R+3.2
1974 John C. Culver (D) D+4.8
1972 Dick Clark (D) D+11.0
1968 Harold E. Hughes (D) D+0.6
1966 Jack Miller (R) R+23.1
1962 Bourke Hickenlooper (R) R+6.8
1960 Jack Miller (R) R+3.8
1956 Bourke Hickenlooper (R) R+7.8
1954 Thomas E. Martin (R) R+4.7
1950 Bourke Hickenlooper (R) R+10.1
1948 Guy M. Gillette (D) D+16.2
1944 Bourke Hickenlooper (R) R+2.9
1942 George A. Wilson (R) R+16.3
1938 Guy M. Gillette (D) D+0.3
1936 Clyde L. Herring (D) D+3.4
1932 Richard L. Murphy (D) D+13.9
1930 Lester Dickinson (R) R+13.3
1926 Smith W. Brookhart (R) R+13.2
1924 Smith W. Brookhart (R) R+0.1
1920 Albert B. Cummins (R) R+24.0
1918 William S. Kenyon (R) R+30.8
1914 Albert B. Cummins (R) R+9.0