| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 3,260 | 6,904 | 10,442 | |
| 2020 | R | 3,995 | 7,063 | 11,297 | |
| 2016 | R | 3,065 | 5,788 | 9,470 | |
| 2012 | R | 3,301 | 5,632 | 9,238 | |
| 2008 | R | 3,734 | 5,910 | 9,879 | |
| 2004 | R | 2,995 | 6,308 | 9,454 | |
| 2000 | R | 2,498 | 5,795 | 8,711 | |
| 1996 | R | 2,841 | 5,041 | 8,866 | |
| 1992 | R | 2,666 | 3,812 | 8,816 | |
| 1988 | R | 2,894 | 4,944 | 7,966 | |
| 1984 | R | 2,488 | 6,020 | 8,632 | |
| 1980 | R | 2,227 | 5,386 | 8,312 | |
| 1976 | R | 3,501 | 4,094 | 7,773 | |
| 1972 | R | 2,681 | 4,569 | 7,743 | |
| 1968 | R | 2,466 | 3,848 | 7,138 | |
| 1964 | D | 3,937 | 3,351 | 7,290 | |
| 1960 | R | 3,410 | 3,911 | 7,356 | |
| 1956 | R | 3,192 | 3,463 | 6,665 | |
| 1952 | R | 2,342 | 4,224 | 6,600 | |
| 1948 | R | 2,578 | 2,819 | 5,528 | |
| 1944 | D | 2,452 | 2,409 | 4,884 | |
| 1940 | D | 3,095 | 2,473 | 5,631 | |
| 1936 | D | 3,288 | 1,620 | 4,984 | |
| 1932 | D | 2,973 | 1,432 | 4,569 | |
| 1928 | R | 1,297 | 2,466 | 3,792 | |
| 1924 | R | 367 | 1,444 | 3,220 | |
| 1920 | R | 902 | 1,916 | 2,985 | |
| 1916 | D | 1,797 | 1,342 | 3,336 | |
| 1912 | D | 1,325 | 0 | 2,435 | |
| 1908 | D | 711 | 618 | 1,382 | |
| 1904 | R | 725 | 765 | 1,529 | |
| 1900 | D | 737 | 494 | 1,251 | |
| 1896 | D | 825 | 479 | 1,311 | |
| 1892 | D | 808 | 528 | 1,563 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Glenn County's economy centers on rice, almonds, and cattle ranching across the flat valley floor, and its rural, agriculture-dependent demographics have produced Republican presidential margins exceeding 30 points in every cycle since 2008.
The Democratic margin in Glenn County peaked at fifty-four points in 1912. By 1968 the county had flipped, voting Republican for the first time in many years. The 2024 margin was thirty-five points, the most Republican-leaning result in the county's modern history.
The economic context is the key. Glenn County's median household income of $67,139 sits well below state and national norms, and 16% 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 Madison County and Beaverhead County.