| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 560 | 2,059 | 2,680 | |
| 2020 | R | 677 | 2,046 | 2,773 | |
| 2016 | R | 739 | 1,721 | 2,571 | |
| 2012 | R | 1,080 | 1,440 | 2,576 | |
| 2008 | D | 1,423 | 1,221 | 2,699 | |
| 2004 | D | 1,367 | 1,317 | 2,706 | |
| 2000 | D | 1,310 | 1,229 | 2,602 | |
| 1996 | D | 1,676 | 941 | 3,013 | |
| 1992 | D | 1,519 | 745 | 2,803 | |
| 1988 | D | 1,544 | 1,238 | 2,790 | |
| 1984 | R | 1,443 | 1,648 | 3,107 | |
| 1980 | R | 1,208 | 1,591 | 2,895 | |
| 1976 | D | 1,549 | 1,364 | 2,943 | |
| 1972 | R | 1,299 | 1,705 | 3,017 | |
| 1968 | R | 1,329 | 1,542 | 3,139 | |
| 1964 | D | 1,805 | 1,288 | 3,093 | |
| 1960 | R | 1,608 | 1,654 | 3,267 | |
| 1956 | R | 1,498 | 1,892 | 3,391 | |
| 1952 | R | 1,454 | 1,915 | 3,371 | |
| 1948 | R | 1,377 | 1,526 | 2,923 | |
| 1944 | R | 1,271 | 1,956 | 3,241 | |
| 1940 | R | 1,625 | 2,516 | 4,158 | |
| 1936 | D | 2,058 | 1,883 | 4,102 | |
| 1932 | D | 2,229 | 1,239 | 3,504 | |
| 1928 | R | 1,551 | 1,594 | 3,178 | |
| 1924 | R | 1,115 | 1,136 | 2,361 | |
| 1920 | R | 703 | 1,367 | 2,109 | |
| 1916 | D | 1,181 | 1,168 | 2,408 | |
| 1912 | D | 602 | 373 | 1,218 | |
| 1908 | D | 905 | 735 | 1,726 | |
| 1904 | D | 815 | 730 | 1,707 | |
| 1900 | D | 1,175 | 873 | 2,079 | |
| 1896 | D | 1,176 | 795 | 1,986 | |
| 1892 | D | 840 | 563 | 1,578 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Calhoun County, wedged between the Illinois and Mississippi rivers with no bridge access on one side, is one of Illinois's least populous counties and has shifted decisively toward Republican presidential candidates over the past two decades, posting a 55-point margin in 2024.
The Republican margin in Calhoun County reached its widest at fifty-six points in 2024. The margin in 2024 was fifty-six points, in line with the county's deep historical pattern.
Calhoun County's loyalty is rooted in its place. Median household income of $93,203, a 94% non-Hispanic-white share, and a population of 4,330 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 Macoupin County and Washington County.