| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 703 | 6,279 | 7,184 | |
| 2020 | R | 657 | 5,845 | 6,664 | |
| 2016 | R | 385 | 3,901 | 5,499 | |
| 2012 | R | 325 | 5,195 | 5,600 | |
| 2008 | R | 600 | 4,246 | 5,073 | |
| 2004 | R | 456 | 4,527 | 5,054 | |
| 2000 | R | 513 | 3,594 | 4,243 | |
| 1996 | R | 807 | 2,435 | 3,892 | |
| 1992 | R | 524 | 2,115 | 4,050 | |
| 1988 | R | 806 | 2,992 | 3,871 | |
| 1984 | R | 439 | 3,261 | 3,742 | |
| 1980 | R | 511 | 3,669 | 4,301 | |
| 1976 | R | 1,157 | 2,720 | 4,012 | |
| 1972 | R | 611 | 2,787 | 3,893 | |
| 1968 | R | 831 | 2,509 | 3,795 | |
| 1964 | R | 1,583 | 2,400 | 3,983 | |
| 1960 | R | 1,352 | 2,633 | 3,985 | |
| 1956 | R | 1,181 | 2,795 | 3,976 | |
| 1952 | R | 1,181 | 3,252 | 4,436 | |
| 1948 | R | 1,763 | 2,028 | 3,813 | |
| 1944 | D | 1,971 | 1,950 | 3,925 | |
| 1940 | D | 2,158 | 2,069 | 4,227 | |
| 1936 | D | 2,255 | 1,396 | 3,670 | |
| 1932 | D | 1,871 | 1,764 | 3,641 | |
| 1928 | R | 1,193 | 1,718 | 2,926 | |
| 1924 | R | 540 | 1,361 | 2,624 | |
| 1920 | R | 899 | 1,612 | 2,511 | |
| 1916 | D | 1,425 | 1,089 | 2,546 | |
| 1912 | — | — | — | — | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Franklin County, tucked into Idaho's southeastern corner near the Utah border, recorded an R+77.9 margin in 2024 — among the widest presidential spreads in the state, reflecting its heavily rural, religiously homogeneous LDS population.
The Republican margin in Franklin County reached its widest at eighty-seven points in 2012. The margin in 2024 was seventy-eight points, in line with the county's deep historical pattern.
Franklin County's loyalty is rooted in its place. Median household income of $71,950, a 91% non-Hispanic-white share, and a population of 15,056 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 Cassia County and Millard County.