| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 23,543 | 59,604 | 84,163 | |
| 2020 | R | 22,422 | 57,245 | 80,783 | |
| 2016 | R | 17,465 | 49,768 | 70,506 | |
| 2012 | R | 18,995 | 43,260 | 63,320 | |
| 2008 | R | 21,169 | 41,906 | 63,641 | |
| 2004 | R | 16,562 | 41,817 | 58,569 | |
| 2000 | R | 14,922 | 33,042 | 49,019 | |
| 1996 | R | 14,980 | 25,392 | 44,730 | |
| 1992 | R | 13,440 | 23,387 | 43,834 | |
| 1988 | R | 12,368 | 27,086 | 39,644 | |
| 1984 | R | 11,480 | 27,243 | 38,845 | |
| 1980 | R | 12,061 | 22,716 | 36,741 | |
| 1976 | R | 14,643 | 20,009 | 35,389 | |
| 1972 | R | 9,456 | 24,093 | 34,415 | |
| 1968 | R | 11,451 | 19,146 | 35,195 | |
| 1964 | D | 19,332 | 13,525 | 32,942 | |
| 1960 | R | 12,088 | 22,010 | 34,134 | |
| 1956 | R | 11,060 | 19,121 | 30,193 | |
| 1952 | R | 8,868 | 16,474 | 25,416 | |
| 1948 | R | 7,352 | 12,151 | 19,664 | |
| 1944 | R | 8,807 | 13,380 | 22,250 | |
| 1940 | R | 12,713 | 13,084 | 25,840 | |
| 1936 | D | 15,632 | 13,616 | 29,413 | |
| 1932 | R | 9,338 | 10,992 | 20,758 | |
| 1928 | R | 3,027 | 16,345 | 19,518 | |
| 1924 | R | 5,770 | 9,791 | 16,645 | |
| 1920 | R | 5,020 | 8,376 | 13,857 | |
| 1916 | R | 5,336 | 5,674 | 11,612 | |
| 1912 | D | 4,505 | 2,710 | 11,523 | |
| 1908 | R | 4,682 | 6,938 | 11,952 | |
| 1904 | R | 4,114 | 7,062 | 11,435 | |
| 1900 | R | 4,500 | 6,483 | 11,182 | |
| 1896 | R | 4,425 | 6,747 | 11,472 | |
| 1892 | R | 4,965 | 5,725 | 10,891 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Anchored by Chambersburg in the Cumberland Valley, Franklin County delivers some of the widest presidential margins in the state, with its agricultural economy and small-city demographics producing consistent double-digit Republican advantages that have deepened each cycle since 2008.
The Republican margin in Franklin County reached its widest at sixty-eight points in 1928. The margin in 2024 was forty-three points, in line with the county's deep historical pattern.
Franklin County's loyalty is rooted in its place. Median household income of $77,003, a 87% non-Hispanic-white share, and a population of 157,379 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 Adams County and Phelps County.