| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 467 | 1,938 | 2,455 | |
| 2020 | R | 486 | 1,931 | 2,525 | |
| 2016 | R | 476 | 1,796 | 2,379 | |
| 2012 | R | 787 | 1,513 | 2,364 | |
| 2008 | R | 986 | 1,544 | 2,569 | |
| 2004 | R | 895 | 1,679 | 2,585 | |
| 2000 | R | 1,077 | 1,529 | 2,660 | |
| 1996 | R | 997 | 1,053 | 2,297 | |
| 1992 | D | 1,146 | 1,029 | 2,689 | |
| 1988 | R | 1,267 | 1,373 | 2,646 | |
| 1984 | R | 959 | 1,478 | 2,446 | |
| 1980 | R | 950 | 1,660 | 2,692 | |
| 1976 | D | 1,533 | 1,519 | 3,103 | |
| 1972 | R | 1,203 | 1,780 | 3,022 | |
| 1968 | R | 1,265 | 1,629 | 3,163 | |
| 1964 | D | 2,083 | 1,355 | 3,438 | |
| 1960 | R | 1,849 | 1,889 | 3,740 | |
| 1956 | R | 1,748 | 2,026 | 3,775 | |
| 1952 | R | 1,557 | 2,137 | 3,699 | |
| 1948 | D | 1,805 | 1,562 | 3,389 | |
| 1944 | D | 1,849 | 1,738 | 3,607 | |
| 1940 | D | 2,478 | 2,101 | 4,648 | |
| 1936 | D | 2,873 | 1,591 | 4,549 | |
| 1932 | D | 2,822 | 1,148 | 3,993 | |
| 1928 | R | 1,867 | 2,289 | 4,165 | |
| 1924 | D | 2,149 | 1,637 | 3,946 | |
| 1920 | D | 1,866 | 1,590 | 3,527 | |
| 1916 | D | 2,856 | 1,579 | 4,572 | |
| 1912 | D | 1,358 | 381 | 2,312 | |
| 1908 | D | 1,609 | 947 | 2,643 | |
| 1904 | D | 1,341 | 934 | 2,452 | |
| 1900 | D | 1,968 | 988 | 3,005 | |
| 1896 | D | 2,063 | 1,024 | 3,117 | |
| 1892 | D | 1,567 | 879 | 2,846 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Brown County's rural, sparsely populated landscape has produced some of the widest presidential margins in the state, with fewer than 7,000 residents concentrated in small towns and farmland along the Illinois River bluffs.
The Democratic margin in Brown County peaked at forty-two points in 1912. By 1996 the county had flipped, voting Republican for the first time in many years. The 2024 margin was sixty points, the most Republican-leaning result in the county's modern history.
The economic context is the key. Brown County's median household income of $67,917 sits well below state and national norms, and 9% 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 Cherokee County and Dallas County.
