| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 1,023 | 5,899 | 7,002 | |
| 2020 | R | 1,067 | 5,707 | 6,863 | |
| 2016 | R | 920 | 5,192 | 6,431 | |
| 2012 | R | 1,423 | 4,978 | 6,509 | |
| 2008 | R | 1,675 | 4,471 | 6,217 | |
| 2004 | R | 1,303 | 4,751 | 6,101 | |
| 2000 | R | 1,313 | 3,918 | 5,342 | |
| 1996 | R | 1,489 | 3,396 | 5,352 | |
| 1992 | R | 1,331 | 3,272 | 5,726 | |
| 1988 | R | 1,706 | 3,517 | 5,264 | |
| 1984 | R | 1,401 | 4,178 | 5,642 | |
| 1980 | R | 1,431 | 4,349 | 6,208 | |
| 1976 | R | 1,870 | 3,558 | 5,554 | |
| 1972 | R | 1,407 | 3,788 | 5,252 | |
| 1968 | R | 1,403 | 4,195 | 5,754 | |
| 1964 | R | 2,747 | 3,185 | 5,935 | |
| 1960 | R | 1,752 | 4,917 | 6,676 | |
| 1956 | R | 1,790 | 4,356 | 6,150 | |
| 1952 | R | 1,324 | 4,893 | 6,226 | |
| 1948 | R | 2,174 | 2,500 | 4,740 | |
| 1944 | R | 1,970 | 3,065 | 5,042 | |
| 1940 | R | 2,648 | 3,880 | 6,540 | |
| 1936 | D | 3,590 | 2,264 | 5,944 | |
| 1932 | D | 3,543 | 1,684 | 5,297 | |
| 1928 | R | 1,632 | 3,170 | 4,838 | |
| 1924 | R | 481 | 2,082 | 4,733 | |
| 1920 | R | 729 | 3,633 | 4,459 | |
| 1916 | R | 1,137 | 1,760 | 2,944 | |
| 1912 | D | 896 | 412 | 2,777 | |
| 1908 | R | 1,064 | 1,650 | 2,800 | |
| 1904 | R | 841 | 1,802 | 2,770 | |
| 1900 | R | 1,289 | 1,666 | 3,029 | |
| 1896 | R | 1,464 | 1,568 | 3,055 | |
| 1892 | D | 1,130 | 1,110 | 2,334 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Lyon County, anchored by Rock Rapids in Iowa's northwest corner, recorded an R+69.6 presidential margin in 2024 — among the widest in the state — reflecting a rural, predominantly Dutch Reformed community that has voted heavily Republican for decades.
The Republican margin in Lyon County reached its widest at seventy points in 2024. The margin in 2024 was seventy points, in line with the county's deep historical pattern.
Lyon County's loyalty is rooted in its place. Median household income of $76,746, a 94% non-Hispanic-white share, and a population of 12,162 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 Clay County and Merrick County.
