| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 904 | 1,341 | 2,271 | |
| 2020 | R | 1,114 | 1,486 | 2,621 | |
| 2016 | R | 1,262 | 1,496 | 2,820 | |
| 2012 | D | 1,965 | 1,487 | 3,501 | |
| 2008 | D | 2,189 | 1,692 | 3,937 | |
| 2004 | D | 2,016 | 1,831 | 3,873 | |
| 2000 | D | 2,357 | 1,588 | 4,022 | |
| 1996 | D | 2,753 | 1,212 | 4,304 | |
| 1992 | D | 2,566 | 1,301 | 4,362 | |
| 1988 | D | 2,693 | 1,954 | 4,663 | |
| 1984 | D | 2,872 | 2,574 | 5,467 | |
| 1980 | D | 2,925 | 2,650 | 5,678 | |
| 1976 | D | 3,246 | 2,349 | 5,658 | |
| 1972 | R | 2,482 | 3,669 | 6,209 | |
| 1968 | D | 2,929 | 2,540 | 6,934 | |
| 1964 | D | 4,763 | 2,895 | 7,658 | |
| 1960 | D | 4,477 | 4,143 | 8,638 | |
| 1956 | R | 4,167 | 4,425 | 8,613 | |
| 1952 | R | 4,305 | 5,219 | 9,553 | |
| 1948 | D | 4,641 | 4,561 | 9,298 | |
| 1944 | R | 4,767 | 4,792 | 9,637 | |
| 1940 | D | 6,591 | 6,260 | 12,988 | |
| 1936 | D | 6,972 | 5,553 | 12,653 | |
| 1932 | D | 5,653 | 4,729 | 10,533 | |
| 1928 | R | 3,558 | 5,666 | 9,252 | |
| 1924 | R | 2,639 | 4,465 | 7,685 | |
| 1920 | R | 3,167 | 5,287 | 8,539 | |
| 1916 | R | 3,940 | 5,395 | 9,498 | |
| 1912 | R | 1,936 | 2,003 | 4,793 | |
| 1908 | R | 2,027 | 3,790 | 5,936 | |
| 1904 | R | 1,686 | 3,203 | 5,075 | |
| 1900 | R | 1,760 | 2,790 | 4,592 | |
| 1896 | R | 1,813 | 2,802 | 4,643 | |
| 1892 | R | 1,674 | 2,053 | 3,807 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Alexander County, anchored by Cairo at the confluence of the Ohio and Mississippi rivers, has undergone one of Illinois's most dramatic partisan realignments, moving from reliably Democratic to Republican-leaning as its population fell by nearly half since 2000.
The Democratic margin in Alexander County has rarely exceeded thirty-six points in modern history; the Republican margin has rarely exceeded thirty points. 2024 delivered the county to the Republican candidate by nineteen points.
Alexander County's demographics resemble the country more than they resemble most counties. A 63% non-Hispanic-white share, a 19% poverty rate, and a median household income of $47,043 — all within the broad national range. The county's voting pattern over the last decade is most similar to that of Quitman County and Bay County.