| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 18,131 | 42,299 | 61,234 | |
| 2020 | R | 18,638 | 40,444 | 60,203 | |
| 2016 | R | 13,024 | 34,252 | 49,750 | |
| 2012 | R | 14,325 | 32,808 | 48,032 | |
| 2008 | R | 15,941 | 32,341 | 48,982 | |
| 2004 | R | 14,944 | 29,735 | 45,006 | |
| 2000 | R | 14,769 | 22,579 | 37,942 | |
| 1996 | R | 13,259 | 18,960 | 34,840 | |
| 1992 | R | 13,071 | 18,206 | 35,483 | |
| 1988 | R | 10,087 | 19,615 | 29,887 | |
| 1984 | R | 9,452 | 21,762 | 31,368 | |
| 1980 | R | 11,599 | 17,457 | 30,249 | |
| 1976 | R | 13,951 | 14,770 | 29,032 | |
| 1972 | R | 5,284 | 17,343 | 23,188 | |
| 1968 | R | 4,930 | 12,882 | 22,737 | |
| 1964 | R | 10,253 | 10,612 | 20,865 | |
| 1960 | R | 6,283 | 14,851 | 21,236 | |
| 1956 | R | 5,314 | 13,471 | 18,912 | |
| 1952 | R | 5,245 | 12,023 | 17,347 | |
| 1948 | R | 4,023 | 7,056 | 11,559 | |
| 1944 | R | 4,060 | 6,485 | 10,602 | |
| 1940 | R | 3,565 | 4,719 | 8,327 | |
| 1936 | R | 4,448 | 4,788 | 9,294 | |
| 1932 | R | 3,345 | 3,691 | 7,138 | |
| 1928 | R | 1,543 | 4,887 | 6,430 | |
| 1924 | R | 1,839 | 3,243 | 5,158 | |
| 1920 | R | 2,260 | 4,858 | 7,122 | |
| 1916 | R | 1,831 | 2,723 | 4,562 | |
| 1912 | D | 1,531 | 1,134 | 4,266 | |
| 1908 | R | 1,574 | 2,254 | 3,835 | |
| 1904 | R | 1,268 | 2,120 | 3,440 | |
| 1900 | R | 1,496 | 2,488 | 4,045 | |
| 1896 | R | 1,661 | 2,807 | 4,529 | |
| 1892 | R | 1,722 | 2,056 | 3,986 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Home to Johnson City and the Appalachian Highlands, Washington County delivers some of Tennessee's most consistent Republican margins, driven by a largely white, working-class electorate that has shifted steadily rightward over the past two decades.
The Republican margin in Washington County reached its widest at fifty-two points in 1928. The margin in 2024 was thirty-nine points, in line with the county's deep historical pattern.
Washington County's loyalty is rooted in its place. Median household income of $62,809, a 87% non-Hispanic-white share, and a population of 136,261 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 Sevier County and Catoosa County.