| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 739 | 3,385 | 4,181 | |
| 2020 | R | 824 | 3,432 | 4,323 | |
| 2016 | R | 802 | 3,206 | 4,156 | |
| 2012 | R | 1,269 | 2,566 | 3,941 | |
| 2008 | R | 1,796 | 2,353 | 4,264 | |
| 2004 | R | 1,814 | 2,653 | 4,514 | |
| 2000 | R | 1,943 | 2,519 | 4,587 | |
| 1996 | D | 2,242 | 1,677 | 4,509 | |
| 1992 | D | 2,582 | 1,521 | 4,974 | |
| 1988 | R | 2,618 | 2,622 | 5,256 | |
| 1984 | R | 2,251 | 3,074 | 5,346 | |
| 1980 | R | 1,990 | 3,254 | 5,456 | |
| 1976 | D | 3,036 | 2,433 | 5,498 | |
| 1972 | R | 2,006 | 3,282 | 5,299 | |
| 1968 | R | 1,951 | 2,912 | 5,513 | |
| 1964 | D | 3,133 | 2,561 | 5,694 | |
| 1960 | R | 2,639 | 3,804 | 6,454 | |
| 1956 | R | 2,685 | 3,675 | 6,364 | |
| 1952 | R | 2,662 | 4,047 | 6,717 | |
| 1948 | R | 2,750 | 2,887 | 5,669 | |
| 1944 | R | 2,914 | 3,582 | 6,551 | |
| 1940 | R | 3,691 | 4,005 | 7,748 | |
| 1936 | D | 4,152 | 3,321 | 7,535 | |
| 1932 | D | 4,059 | 2,513 | 6,617 | |
| 1928 | R | 3,037 | 3,275 | 6,412 | |
| 1924 | D | 3,168 | 2,659 | 6,041 | |
| 1920 | R | 2,591 | 3,220 | 5,886 | |
| 1916 | D | 3,644 | 3,239 | 6,996 | |
| 1912 | D | 1,920 | 1,242 | 3,964 | |
| 1908 | D | 2,128 | 1,809 | 4,087 | |
| 1904 | D | 2,049 | 1,894 | 4,149 | |
| 1900 | D | 2,467 | 1,911 | 4,449 | |
| 1896 | D | 2,408 | 1,767 | 4,215 | |
| 1892 | D | 2,061 | 1,505 | 3,781 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Hamilton County, in deep southern Illinois, recorded an R+63.3 presidential margin in 2024, reflecting the region's sharp rightward shift over the past two decades as rural downstate communities have diverged from the Chicago metro.
The Democratic margin in Hamilton County peaked at twenty-three points in 1932. By 2000 the county had flipped, voting Republican for the first time in many years. The 2024 margin was sixty-three points, the most Republican-leaning result in the county's modern history.
The economic context is the key. Hamilton County's median household income of $65,746 sits well below state and national norms, and 12% of residents live below the federal poverty line. The shift here is part of a broader realignment of working-class places across the country. The county's voting pattern over the last decade is most similar to that of Henry County and Chariton County.