| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 16,624 | 58,154 | 75,541 | |
| 2020 | R | 17,272 | 55,860 | 74,357 | |
| 2016 | R | 12,578 | 46,979 | 62,278 | |
| 2012 | R | 15,321 | 43,562 | 59,887 | |
| 2008 | R | 18,354 | 44,808 | 63,997 | |
| 2004 | R | 19,637 | 42,555 | 62,639 | |
| 2000 | R | 21,354 | 33,482 | 55,727 | |
| 1996 | R | 20,571 | 29,296 | 53,837 | |
| 1992 | R | 20,935 | 28,801 | 56,980 | |
| 1988 | R | 17,396 | 32,996 | 50,977 | |
| 1984 | R | 16,925 | 36,516 | 53,835 | |
| 1980 | R | 22,341 | 25,963 | 50,470 | |
| 1976 | D | 23,353 | 22,087 | 46,762 | |
| 1972 | R | 10,007 | 27,593 | 38,517 | |
| 1968 | R | 9,783 | 20,251 | 40,025 | |
| 1964 | D | 19,496 | 17,703 | 37,199 | |
| 1960 | R | 14,731 | 22,354 | 37,598 | |
| 1956 | R | 14,106 | 18,903 | 33,506 | |
| 1952 | R | 11,849 | 15,596 | 27,563 | |
| 1948 | D | 7,626 | 6,984 | 15,120 | |
| 1944 | D | 6,290 | 5,223 | 11,544 | |
| 1940 | D | 7,234 | 4,153 | 11,421 | |
| 1936 | D | 6,269 | 3,492 | 9,795 | |
| 1932 | D | 5,322 | 2,999 | 8,442 | |
| 1928 | R | 3,216 | 4,149 | 7,365 | |
| 1924 | D | 3,313 | 2,247 | 5,625 | |
| 1920 | D | 4,327 | 3,593 | 7,920 | |
| 1916 | D | 2,601 | 1,776 | 4,384 | |
| 1912 | D | 2,413 | 538 | 4,228 | |
| 1908 | D | 2,393 | 1,836 | 4,261 | |
| 1904 | D | 2,116 | 1,506 | 3,668 | |
| 1900 | D | 2,421 | 1,739 | 4,216 | |
| 1896 | D | 2,512 | 1,914 | 4,482 | |
| 1892 | D | 2,281 | 1,304 | 3,921 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Sullivan County anchors the Tri-Cities region of northeast Tennessee, where a blue-collar manufacturing and healthcare workforce has moved steadily toward Republican dominance over the past two decades, producing some of the widest presidential margins in the state.
The Democratic margin in Sullivan County peaked at forty-four points in 1912. By 1980 the county had flipped, voting Republican for the first time in many years. The 2024 margin was fifty-five points, the most Republican-leaning result in the county's modern history.
The economic context is the key. Sullivan County's median household income of $58,807 sits well below state and national norms, and 15% 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 Morgan County and Jefferson County.