| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 7,935 | 10,794 | 19,054 | |
| 2020 | R | 8,893 | 10,592 | 19,956 | |
| 2016 | R | 8,212 | 9,529 | 19,271 | |
| 2012 | D | 11,888 | 8,136 | 20,385 | |
| 2008 | D | 12,462 | 7,721 | 20,570 | |
| 2004 | D | 12,456 | 8,221 | 20,874 | |
| 2000 | D | 11,351 | 7,385 | 19,365 | |
| 1996 | D | 10,761 | 5,778 | 18,574 | |
| 1992 | D | 11,309 | 6,378 | 21,190 | |
| 1988 | D | 11,593 | 7,652 | 19,374 | |
| 1984 | D | 11,173 | 9,559 | 20,850 | |
| 1980 | D | 9,977 | 9,158 | 20,417 | |
| 1976 | D | 11,268 | 9,023 | 20,536 | |
| 1972 | R | 8,869 | 10,216 | 19,358 | |
| 1968 | D | 10,164 | 8,452 | 19,979 | |
| 1964 | D | 13,894 | 5,830 | 19,762 | |
| 1960 | R | 9,872 | 10,678 | 20,591 | |
| 1956 | R | 8,781 | 11,152 | 19,958 | |
| 1952 | R | 8,686 | 12,182 | 20,957 | |
| 1948 | D | 8,792 | 7,621 | 16,729 | |
| 1944 | R | 7,543 | 9,488 | 17,177 | |
| 1940 | R | 6,578 | 10,988 | 17,625 | |
| 1936 | D | 7,011 | 6,763 | 15,705 | |
| 1932 | D | 9,395 | 5,590 | 15,675 | |
| 1928 | R | 5,578 | 10,547 | 16,302 | |
| 1924 | R | 2,616 | 7,995 | 14,810 | |
| 1920 | R | 3,449 | 8,287 | 12,997 | |
| 1916 | R | 3,827 | 4,132 | 8,345 | |
| 1912 | D | 3,169 | 2,136 | 8,064 | |
| 1908 | R | 3,975 | 4,153 | 8,489 | |
| 1904 | R | 3,043 | 4,496 | 8,299 | |
| 1900 | R | 3,909 | 4,315 | 8,508 | |
| 1896 | R | 3,741 | 4,549 | 8,574 | |
| 1892 | D | 4,526 | 3,361 | 7,996 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Des Moines County anchors Iowa's southeastern corner at the confluence of the Iowa and Mississippi rivers. Once a reliably competitive bellwether, it has trended Republican in each of the last three presidential cycles, landing at R+15 in 2024.
The Democratic margin in Des Moines County has rarely exceeded forty-one points in modern history; the Republican margin has rarely exceeded thirty-seven points. 2024 delivered the county to the Republican candidate by fifteen points.
Des Moines County's demographics resemble the country more than they resemble most counties. A 86% non-Hispanic-white share, a 13% poverty rate, and a median household income of $62,928 — all within the broad national range. The county's voting pattern over the last decade is most similar to that of Trumbull County and Mower County.
