| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 26,011 | 29,536 | 57,802 | |
| 2020 | R | 27,174 | 29,551 | 58,923 | |
| 2016 | R | 19,301 | 23,250 | 48,753 | |
| 2012 | R | 19,260 | 22,045 | 42,907 | |
| 2008 | R | 20,797 | 21,390 | 43,526 | |
| 2004 | R | 17,572 | 23,839 | 42,142 | |
| 2000 | R | 14,254 | 19,193 | 35,539 | |
| 1996 | R | 13,078 | 13,900 | 31,135 | |
| 1992 | R | 11,148 | 11,693 | 31,406 | |
| 1988 | R | 11,423 | 13,321 | 25,388 | |
| 1984 | R | 9,450 | 15,797 | 25,351 | |
| 1980 | R | 8,694 | 12,054 | 23,568 | |
| 1976 | R | 8,881 | 9,885 | 19,620 | |
| 1972 | R | 6,008 | 9,660 | 16,509 | |
| 1968 | R | 5,487 | 7,936 | 14,285 | |
| 1964 | D | 8,949 | 5,508 | 14,463 | |
| 1960 | R | 5,528 | 8,295 | 13,829 | |
| 1956 | R | 5,253 | 8,555 | 13,808 | |
| 1952 | R | 4,472 | 9,332 | 13,872 | |
| 1948 | R | 4,794 | 6,379 | 11,528 | |
| 1944 | R | 5,067 | 5,672 | 11,037 | |
| 1940 | D | 5,566 | 5,545 | 11,207 | |
| 1936 | D | 5,366 | 3,443 | 9,596 | |
| 1932 | D | 4,798 | 3,584 | 8,719 | |
| 1928 | R | 2,382 | 5,248 | 7,721 | |
| 1924 | R | 2,015 | 3,803 | 7,160 | |
| 1920 | R | 2,353 | 4,102 | 6,895 | |
| 1916 | R | 3,342 | 4,010 | 8,028 | |
| 1912 | D | 1,378 | 1,312 | 4,196 | |
| 1908 | R | 1,246 | 1,980 | 3,634 | |
| 1904 | R | 652 | 2,004 | 3,174 | |
| 1900 | R | 1,235 | 1,583 | 3,024 | |
| 1896 | R | 1,736 | 1,782 | 3,724 | |
| 1892 | R | 682 | 1,469 | 3,183 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Yamhill sits in Oregon's Willamette Valley wine region, where small cities like McMinnville anchor a population that has shifted modestly toward Republican margins over successive presidential cycles despite the area's agricultural and tourism economy drawing a mixed demographic.
The Democratic margin in Yamhill County has rarely exceeded twenty-four points in modern history; the Republican margin has rarely exceeded forty-three points. 2024 delivered the county to the Republican candidate by six points.
Yamhill County's demographics resemble the country more than they resemble most counties. A 77% non-Hispanic-white share, a 10% poverty rate, and a median household income of $90,063 — all within the broad national range. The county's voting pattern over the last decade is most similar to that of Polk County and Jackson County.