| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 357 | 1,546 | 1,926 | |
| 2020 | R | 449 | 1,691 | 2,162 | |
| 2016 | R | 420 | 1,653 | 2,148 | |
| 2012 | R | 742 | 1,535 | 2,330 | |
| 2008 | R | 892 | 1,330 | 2,255 | |
| 2004 | R | 923 | 1,501 | 2,437 | |
| 2000 | R | 1,184 | 1,366 | 2,637 | |
| 1996 | D | 1,323 | 790 | 2,617 | |
| 1992 | D | 1,665 | 985 | 3,173 | |
| 1988 | R | 1,308 | 1,504 | 2,824 | |
| 1984 | R | 1,205 | 1,689 | 2,899 | |
| 1980 | R | 1,314 | 1,721 | 3,114 | |
| 1976 | D | 1,602 | 1,393 | 3,017 | |
| 1972 | R | 1,140 | 1,915 | 3,062 | |
| 1968 | R | 1,199 | 1,492 | 2,883 | |
| 1964 | D | 1,639 | 1,324 | 2,963 | |
| 1960 | R | 1,465 | 1,944 | 3,413 | |
| 1956 | R | 1,444 | 1,919 | 3,371 | |
| 1952 | R | 1,563 | 1,984 | 3,553 | |
| 1948 | R | 1,358 | 1,713 | 3,087 | |
| 1944 | R | 1,370 | 2,037 | 3,438 | |
| 1940 | R | 1,974 | 2,333 | 4,333 | |
| 1936 | R | 1,984 | 2,008 | 4,011 | |
| 1932 | D | 1,610 | 1,559 | 3,223 | |
| 1928 | R | 933 | 1,758 | 2,732 | |
| 1924 | R | 1,358 | 1,378 | 2,809 | |
| 1920 | R | 943 | 1,555 | 2,527 | |
| 1916 | R | 1,264 | 1,419 | 2,746 | |
| 1912 | R | 644 | 691 | 1,585 | |
| 1908 | R | 680 | 813 | 1,548 | |
| 1904 | R | 642 | 756 | 1,540 | |
| 1900 | D | 839 | 753 | 1,626 | |
| 1896 | D | 900 | 780 | 1,690 | |
| 1892 | D | 700 | 660 | 1,531 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Hardin County sits at the southeastern tip of Illinois along the Ohio River, where a sparse, rural population has produced some of the state's widest Republican presidential margins over the past decade.
The Democratic margin in Hardin County peaked at twenty-one points in 1992. By 2000 the county had flipped, voting Republican for the first time in many years. The 2024 margin was sixty-two points, the most Republican-leaning result in the county's modern history.
The economic context is the key. Hardin County's median household income of $54,271 sits well below state and national norms, and 11% 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 Union County and Henry County.