| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | D | 24,595 | 9,218 | 35,647 | |
| 2020 | D | 25,191 | 8,928 | 35,307 | |
| 2016 | D | 18,594 | 7,993 | 31,086 | |
| 2012 | D | 20,351 | 8,093 | 29,307 | |
| 2008 | D | 22,324 | 9,129 | 32,200 | |
| 2004 | D | 19,177 | 11,461 | 31,448 | |
| 2000 | D | 15,281 | 11,448 | 29,749 | |
| 1996 | D | 14,267 | 7,750 | 25,884 | |
| 1992 | D | 13,452 | 9,424 | 29,338 | |
| 1988 | R | 12,690 | 13,253 | 26,294 | |
| 1984 | R | 11,163 | 13,706 | 25,158 | |
| 1980 | R | 9,559 | 9,714 | 23,151 | |
| 1976 | R | 8,764 | 10,919 | 20,259 | |
| 1972 | R | 7,596 | 12,421 | 20,169 | |
| 1968 | R | 7,826 | 9,387 | 17,839 | |
| 1964 | D | 12,002 | 5,750 | 17,763 | |
| 1960 | R | 7,116 | 10,458 | 17,578 | |
| 1956 | R | 4,520 | 11,351 | 15,876 | |
| 1952 | R | 4,460 | 11,979 | 16,503 | |
| 1948 | R | 4,839 | 7,720 | 12,883 | |
| 1944 | R | 5,749 | 7,162 | 12,911 | |
| 1940 | R | 7,727 | 8,426 | 16,203 | |
| 1936 | R | 8,073 | 8,351 | 16,490 | |
| 1932 | R | 5,777 | 8,393 | 14,540 | |
| 1928 | R | 4,408 | 9,891 | 14,353 | |
| 1924 | R | 1,715 | 8,525 | 11,474 | |
| 1920 | R | 1,953 | 6,418 | 8,471 | |
| 1916 | R | 2,732 | 4,216 | 7,382 | |
| 1912 | R | 1,743 | 2,797 | 6,779 | |
| 1908 | R | 1,610 | 3,823 | 5,634 | |
| 1904 | R | 1,247 | 3,807 | 5,282 | |
| 1900 | R | 1,622 | 3,819 | 5,540 | |
| 1896 | R | 1,396 | 4,476 | 6,123 | |
| 1892 | R | 1,940 | 3,134 | 5,199 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Washington County's D+43 margin in 2024 reflects the outsized influence of Montpelier's government and university workforce on a county of fewer than 60,000 residents, making it one of the most reliably Democratic jurisdictions in New England.
The unraveling was not abrupt. The Democratic margin in Washington County peaked at forty-six points in 2020; it narrowed steadily over the late twentieth century. The 1992 election delivered the county to the Republican party for the first time in many years, by a margin of fourteen points. By 2024, the margin had widened further.
The economic and demographic context is severe. Washington County's median household income of $83,449 is among the lowest of any county in the United States; 9% of residents live below the federal poverty line. The county's voting pattern over the last decade is most similar to that of Windsor County and Addison County.