| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 975 | 1,165 | 2,183 | |
| 2020 | R | 1,112 | 1,142 | 2,304 | |
| 2016 | R | 930 | 991 | 2,088 | |
| 2012 | D | 1,276 | 871 | 2,182 | |
| 2008 | D | 1,436 | 843 | 2,343 | |
| 2004 | D | 1,339 | 1,132 | 2,508 | |
| 2000 | R | 921 | 1,122 | 2,224 | |
| 1996 | D | 1,026 | 877 | 2,209 | |
| 1992 | D | 1,035 | 854 | 2,389 | |
| 1988 | D | 1,277 | 1,051 | 2,358 | |
| 1984 | R | 1,241 | 1,328 | 2,597 | |
| 1980 | R | 1,175 | 1,275 | 2,635 | |
| 1976 | D | 1,590 | 905 | 2,613 | |
| 1972 | D | 1,397 | 1,246 | 2,691 | |
| 1968 | D | 1,508 | 893 | 2,605 | |
| 1964 | D | 1,967 | 648 | 2,619 | |
| 1960 | D | 1,864 | 880 | 2,749 | |
| 1956 | D | 1,513 | 875 | 2,392 | |
| 1952 | D | 1,436 | 1,220 | 2,660 | |
| 1948 | D | 2,125 | 579 | 2,775 | |
| 1944 | D | 1,494 | 748 | 2,260 | |
| 1940 | D | 1,959 | 1,069 | 3,042 | |
| 1936 | D | 2,025 | 474 | 2,634 | |
| 1932 | D | 1,734 | 264 | 2,069 | |
| 1928 | D | 1,378 | 606 | 2,027 | |
| 1924 | R | 122 | 629 | 1,867 | |
| 1920 | R | 215 | 1,076 | 1,495 | |
| 1916 | D | 411 | 262 | 720 | |
| 1912 | D | 293 | 68 | 625 | |
| 1908 | R | 143 | 265 | 494 | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Mahnomen County sits entirely within the White Earth Nation reservation, giving it a Native American majority and a political profile distinct from surrounding rural Minnesota — one that has shifted notably rightward over recent cycles.
The county's recent history is a story of close margins. The Democratic margin reached seventy-one points in 1932; the Republican margin reached fifty-eight points in 1920. Most other elections have been decided by single-digit points.
Mahnomen County's demographics — a population of 5,358, a 45% non-Hispanic-white share, a median household income of $59,441 — situate the county close to national averages on several dimensions. The county's voting pattern over the last decade is most similar to that of Winneshiek County and Benson County.
