| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | D | 7,750 | 6,631 | 14,677 | |
| 2020 | D | 7,828 | 5,909 | 13,992 | |
| 2016 | D | 6,669 | 4,809 | 12,275 | |
| 2012 | D | 8,105 | 4,287 | 12,534 | |
| 2008 | D | 7,987 | 3,829 | 11,969 | |
| 2004 | D | 7,122 | 5,348 | 12,542 | |
| 2000 | D | 5,842 | 4,221 | 10,541 | |
| 1996 | D | 4,690 | 2,866 | 8,916 | |
| 1992 | D | 4,467 | 3,288 | 10,151 | |
| 1988 | D | 4,268 | 4,240 | 8,548 | |
| 1984 | R | 3,843 | 4,983 | 8,897 | |
| 1980 | D | 4,154 | 4,068 | 8,992 | |
| 1976 | D | 4,252 | 4,195 | 8,678 | |
| 1972 | R | 3,131 | 4,387 | 7,626 | |
| 1968 | R | 2,897 | 4,005 | 7,413 | |
| 1964 | D | 4,620 | 3,275 | 7,907 | |
| 1960 | R | 3,547 | 5,143 | 8,694 | |
| 1956 | R | 3,176 | 5,201 | 8,417 | |
| 1952 | R | 2,722 | 6,211 | 8,952 | |
| 1948 | D | 3,917 | 3,745 | 7,794 | |
| 1944 | R | 3,585 | 4,608 | 8,228 | |
| 1940 | R | 4,025 | 4,978 | 9,140 | |
| 1936 | D | 4,988 | 3,623 | 9,094 | |
| 1932 | D | 4,621 | 3,113 | 7,856 | |
| 1928 | R | 3,129 | 5,484 | 8,669 | |
| 1924 | R | 689 | 3,291 | 8,213 | |
| 1920 | R | 942 | 5,428 | 6,667 | |
| 1916 | R | 2,230 | 2,271 | 4,656 | |
| 1912 | D | 2,103 | 1,886 | 4,684 | |
| 1908 | R | 2,077 | 2,986 | 5,315 | |
| 1904 | R | 1,639 | 3,328 | 5,153 | |
| 1900 | R | 1,743 | 3,270 | 5,231 | |
| 1896 | R | 2,060 | 3,115 | 5,425 | |
| 1892 | D | 2,336 | 2,274 | 4,995 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Iowa County, Wisconsin posted a D+7.6 margin in 2024, an outlier relative to surrounding rural counties. Its mix of small-farm communities and proximity to university-influenced Dodgeville anchors a persistently center-left tilt.
The Democratic margin in Iowa County reached its widest at thirty-five points in 2008. The margin in 2024 was eight points — still decisive.
Iowa County's loyalty is rooted in its place. Median household income of $82,182, a 93% non-Hispanic-white share, and a population of 23,867 together describe a community whose political habits are deeply settled. The county's voting pattern over the last decade is most similar to that of Rock County and La Crosse County.
