| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 4,343 | 17,146 | 21,766 | |
| 2020 | R | 4,493 | 17,022 | 21,809 | |
| 2016 | R | 4,325 | 15,446 | 20,887 | |
| 2012 | R | 6,211 | 13,535 | 20,404 | |
| 2008 | R | 6,999 | 13,562 | 21,049 | |
| 2004 | R | 7,274 | 13,734 | 21,127 | |
| 2000 | R | 6,375 | 11,176 | 18,166 | |
| 1996 | R | 6,611 | 8,139 | 17,133 | |
| 1992 | R | 5,557 | 8,023 | 18,098 | |
| 1988 | R | 4,937 | 10,297 | 15,381 | |
| 1984 | R | 4,198 | 11,065 | 15,403 | |
| 1980 | R | 5,416 | 8,376 | 14,723 | |
| 1976 | R | 5,850 | 6,654 | 12,747 | |
| 1972 | R | 3,472 | 8,993 | 12,795 | |
| 1968 | R | 3,817 | 6,544 | 12,434 | |
| 1964 | D | 7,574 | 5,839 | 13,413 | |
| 1960 | R | 5,467 | 8,802 | 14,269 | |
| 1956 | R | 4,574 | 8,099 | 12,673 | |
| 1952 | R | 4,836 | 8,405 | 13,241 | |
| 1948 | R | 4,656 | 5,837 | 10,516 | |
| 1944 | R | 4,872 | 6,609 | 11,481 | |
| 1940 | R | 5,735 | 6,511 | 12,246 | |
| 1936 | D | 6,366 | 5,593 | 12,290 | |
| 1932 | D | 6,221 | 5,205 | 11,625 | |
| 1928 | R | 3,513 | 6,693 | 10,263 | |
| 1924 | R | 4,033 | 5,676 | 10,001 | |
| 1920 | R | 4,933 | 6,258 | 11,231 | |
| 1916 | D | 3,387 | 2,881 | 6,380 | |
| 1912 | D | 2,859 | 2,135 | 6,158 | |
| 1908 | R | 3,247 | 3,519 | 6,901 | |
| 1904 | R | 2,792 | 3,647 | 6,649 | |
| 1900 | R | 3,206 | 3,548 | 6,899 | |
| 1896 | R | 3,254 | 3,300 | 6,659 | |
| 1892 | R | 2,699 | 2,957 | 5,987 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
A rural county of roughly 42,000 residents wedged between Dayton and the Indiana border, Preble has drifted steadily toward supermajority Republican margins over the past two decades, reflecting a broader pattern of rural consolidation across southwestern Ohio.
The Republican margin in Preble County reached its widest at fifty-nine points in 2024. The margin in 2024 was fifty-nine points, in line with the county's deep historical pattern.
Preble County's loyalty is rooted in its place. Median household income of $69,223, a 96% non-Hispanic-white share, and a population of 40,765 together describe a community whose political habits are deeply settled. The county's voting pattern over the last decade is most similar to that of Darke County and Carroll County.