| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 5,233 | 14,830 | 20,448 | |
| 2020 | R | 5,343 | 14,565 | 20,236 | |
| 2016 | R | 4,776 | 12,933 | 18,541 | |
| 2012 | R | 6,607 | 10,640 | 17,671 | |
| 2008 | R | 7,288 | 10,551 | 18,091 | |
| 2004 | R | 6,171 | 11,015 | 17,310 | |
| 2000 | R | 5,870 | 8,711 | 14,896 | |
| 1996 | R | 5,900 | 6,073 | 13,885 | |
| 1992 | D | 5,768 | 5,403 | 13,671 | |
| 1988 | R | 4,933 | 6,702 | 11,661 | |
| 1984 | R | 4,634 | 7,255 | 11,969 | |
| 1980 | R | 4,865 | 6,287 | 11,594 | |
| 1976 | D | 5,685 | 4,911 | 10,699 | |
| 1972 | R | 3,927 | 5,910 | 9,888 | |
| 1968 | R | 3,725 | 4,410 | 9,731 | |
| 1964 | D | 5,949 | 3,671 | 9,708 | |
| 1960 | R | 4,566 | 5,374 | 9,989 | |
| 1956 | R | 4,266 | 5,299 | 9,648 | |
| 1952 | R | 4,213 | 5,069 | 9,454 | |
| 1948 | D | 4,465 | 4,104 | 8,751 | |
| 1944 | R | 4,285 | 4,397 | 8,786 | |
| 1940 | D | 4,725 | 4,650 | 9,439 | |
| 1936 | D | 5,025 | 3,885 | 8,986 | |
| 1932 | D | 5,128 | 3,553 | 8,804 | |
| 1928 | R | 3,664 | 4,440 | 8,158 | |
| 1924 | D | 4,005 | 3,896 | 8,064 | |
| 1920 | R | 3,898 | 4,271 | 8,301 | |
| 1916 | D | 2,373 | 2,086 | 4,639 | |
| 1912 | D | 2,106 | 900 | 4,449 | |
| 1908 | D | 2,646 | 2,419 | 5,239 | |
| 1904 | R | 2,530 | 2,544 | 5,290 | |
| 1900 | D | 2,824 | 2,482 | 5,405 | |
| 1896 | D | 2,813 | 2,486 | 5,349 | |
| 1892 | D | 2,464 | 2,114 | 4,832 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Harrison County, tucked against the Ohio River in southern Indiana, backed the Republican presidential candidate by nearly 47 points in 2024, reflecting the deep-red realignment that has reshaped rural river-county politics across the Ohio Valley over the past decade.
The Republican margin in Harrison County reached its widest at forty-seven points in 2024. The margin in 2024 was forty-seven points, in line with the county's deep historical pattern.
Harrison County's loyalty is rooted in its place. Median household income of $74,475, a 95% non-Hispanic-white share, and a population of 39,859 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 Grant County and Washington County.