| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 16,326 | 26,417 | 42,843 | |
| 2020 | R | 17,307 | 25,629 | 43,855 | |
| 2016 | R | 13,809 | 21,763 | 38,236 | |
| 2012 | R | 17,099 | 18,122 | 35,708 | |
| 2008 | R | 18,166 | 20,220 | 38,886 | |
| 2004 | R | 16,860 | 21,231 | 38,800 | |
| 2000 | R | 16,799 | 18,192 | 36,423 | |
| 1996 | D | 16,783 | 12,362 | 34,127 | |
| 1992 | R | 13,380 | 14,227 | 37,426 | |
| 1988 | R | 14,137 | 19,304 | 33,622 | |
| 1984 | R | 10,960 | 23,445 | 34,496 | |
| 1980 | R | 13,271 | 16,455 | 33,128 | |
| 1976 | R | 13,503 | 20,401 | 34,028 | |
| 1972 | R | 11,629 | 23,123 | 34,817 | |
| 1968 | R | 13,438 | 18,552 | 33,109 | |
| 1964 | D | 25,175 | 10,718 | 35,914 | |
| 1960 | R | 15,800 | 24,290 | 40,115 | |
| 1956 | R | 9,959 | 28,429 | 38,388 | |
| 1952 | R | 12,026 | 27,932 | 39,983 | |
| 1948 | R | 13,176 | 19,661 | 33,351 | |
| 1944 | R | 14,449 | 21,834 | 36,329 | |
| 1940 | R | 14,581 | 25,584 | 40,262 | |
| 1936 | R | 13,975 | 24,925 | 39,466 | |
| 1932 | R | 13,478 | 22,760 | 36,724 | |
| 1928 | R | 12,908 | 26,361 | 39,695 | |
| 1924 | R | 7,665 | 21,159 | 30,942 | |
| 1920 | R | 7,925 | 22,072 | 31,201 | |
| 1916 | R | 7,089 | 11,197 | 19,081 | |
| 1912 | R | 6,054 | 6,692 | 17,624 | |
| 1908 | R | 6,694 | 11,477 | 19,813 | |
| 1904 | R | 6,696 | 12,050 | 19,893 | |
| 1900 | R | 6,776 | 11,870 | 19,451 | |
| 1896 | R | 6,644 | 11,411 | 18,744 | |
| 1892 | R | 7,181 | 9,856 | 18,146 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Jefferson County's large active-duty military population at Fort Drum shapes both its demographics and its electoral patterns, contributing to a consistent Republican margin that reached double digits well before 2024.
The Republican margin in Jefferson County reached its widest at forty-eight points in 1956. The margin in 2024 was twenty-four points, in line with the county's deep historical pattern.
Jefferson County's loyalty is rooted in its place. Median household income of $66,301, a 83% non-Hispanic-white share, and a population of 115,040 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 Chemung County and Steele County.
