| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 4,707 | 18,235 | 23,183 | |
| 2020 | R | 4,527 | 17,960 | 22,824 | |
| 2016 | R | 3,650 | 15,192 | 19,595 | |
| 2012 | R | 4,787 | 13,048 | 18,178 | |
| 2008 | R | 6,447 | 12,057 | 18,802 | |
| 2004 | R | 6,073 | 13,371 | 19,560 | |
| 2000 | R | 5,566 | 11,473 | 17,586 | |
| 1996 | R | 5,846 | 8,156 | 16,457 | |
| 1992 | R | 5,998 | 7,271 | 17,711 | |
| 1988 | R | 6,235 | 9,743 | 16,109 | |
| 1984 | R | 5,950 | 11,334 | 17,355 | |
| 1980 | R | 6,296 | 9,628 | 16,778 | |
| 1976 | R | 7,456 | 9,437 | 17,130 | |
| 1972 | R | 5,024 | 11,631 | 16,876 | |
| 1968 | R | 6,839 | 10,214 | 18,347 | |
| 1964 | D | 10,851 | 8,373 | 19,261 | |
| 1960 | R | 7,811 | 13,845 | 21,694 | |
| 1956 | R | 6,627 | 13,051 | 19,697 | |
| 1952 | R | 6,365 | 11,833 | 18,314 | |
| 1948 | R | 5,632 | 9,395 | 15,295 | |
| 1944 | R | 6,425 | 10,970 | 17,547 | |
| 1940 | R | 8,559 | 12,081 | 20,687 | |
| 1936 | R | 11,080 | 11,943 | 23,306 | |
| 1932 | R | 6,570 | 8,246 | 15,713 | |
| 1928 | R | 4,325 | 13,233 | 17,731 | |
| 1924 | R | 2,664 | 10,673 | 16,450 | |
| 1920 | R | 3,060 | 7,970 | 11,950 | |
| 1916 | R | 3,253 | 4,332 | 8,373 | |
| 1912 | D | 2,510 | 1,608 | 8,622 | |
| 1908 | R | 2,986 | 5,652 | 9,393 | |
| 1904 | R | 2,095 | 5,860 | 8,482 | |
| 1900 | R | 3,063 | 5,950 | 9,538 | |
| 1896 | R | 3,671 | 5,500 | 9,619 | |
| 1892 | R | 3,251 | 4,100 | 8,133 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
A rural, heavily forested county in the Allegheny Plateau, Jefferson delivered a 58.5-point Republican presidential margin in 2024—among the widest gaps in a state defined by its competitive, closely divided major metros.
The Democratic margin in Jefferson County peaked at thirteen points in 1964. By 1968 the county had flipped, voting Republican for the first time in many years. The 2024 margin was fifty-eight points, the most Republican-leaning result in the county's modern history.
The economic context is the key. Jefferson County's median household income of $58,686 sits well below state and national norms, and 14% 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 Wayne County and Edwards County.