| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | D | 11,394 | 10,614 | 22,465 | |
| 2020 | D | 11,181 | 10,890 | 22,718 | |
| 2016 | D | 11,634 | 10,843 | 24,617 | |
| 2012 | D | 13,319 | 9,864 | 24,104 | |
| 2008 | D | 15,248 | 9,687 | 25,532 | |
| 2004 | D | 14,300 | 11,190 | 25,826 | |
| 2000 | D | 11,773 | 9,823 | 23,090 | |
| 1996 | D | 12,214 | 7,422 | 22,011 | |
| 1992 | D | 13,373 | 6,899 | 24,434 | |
| 1988 | D | 11,334 | 9,687 | 21,185 | |
| 1984 | R | 12,105 | 13,609 | 25,896 | |
| 1980 | R | 10,291 | 10,505 | 23,829 | |
| 1976 | D | 12,940 | 10,152 | 24,122 | |
| 1972 | D | 13,146 | 12,393 | 25,594 | |
| 1968 | R | 8,856 | 9,134 | 19,657 | |
| 1964 | D | 12,165 | 7,013 | 19,178 | |
| 1960 | R | 8,527 | 10,568 | 19,112 | |
| 1956 | R | 7,391 | 10,526 | 17,927 | |
| 1952 | R | 7,457 | 10,193 | 17,674 | |
| 1948 | R | 6,939 | 8,288 | 15,408 | |
| 1944 | R | 6,735 | 10,002 | 16,791 | |
| 1940 | R | 9,600 | 11,980 | 21,708 | |
| 1936 | R | 9,971 | 10,363 | 20,546 | |
| 1932 | D | 9,730 | 7,636 | 17,715 | |
| 1928 | R | 5,836 | 9,180 | 15,102 | |
| 1924 | R | 4,707 | 6,424 | 13,030 | |
| 1920 | R | 4,575 | 8,003 | 13,347 | |
| 1916 | R | 6,780 | 8,356 | 15,443 | |
| 1912 | D | 3,323 | 2,780 | 7,833 | |
| 1908 | R | 3,149 | 4,016 | 7,568 | |
| 1904 | R | 2,350 | 3,984 | 7,076 | |
| 1900 | R | 3,723 | 4,054 | 7,954 | |
| 1896 | R | 3,631 | 3,879 | 7,620 | |
| 1892 | R | 2,858 | 3,031 | 6,460 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Home to Southern Illinois University in Carbondale, Jackson County votes modestly left of its rural neighbors — a pattern driven by the student and faculty population anchoring an otherwise small-city, working-class electorate.
The county's recent history is a story of close margins. The Democratic margin reached twenty-seven points in 1964; the Republican margin reached twenty-six points in 1920. Most other elections have been decided by single-digit points.
Jackson County's demographics — a population of 53,064, a 73% non-Hispanic-white share, a median household income of $48,763 — situate the county close to national averages on several dimensions. The county's voting pattern over the last decade is most similar to that of Grant County and St. Clair County.
