| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 5,978 | 8,575 | 14,939 | |
| 2020 | R | 6,110 | 8,000 | 14,567 | |
| 2016 | R | 4,879 | 6,748 | 12,680 | |
| 2012 | R | 5,827 | 6,220 | 12,400 | |
| 2008 | D | 7,207 | 6,431 | 13,945 | |
| 2004 | R | 5,443 | 7,662 | 13,375 | |
| 2000 | D | 6,212 | 4,546 | 10,984 | |
| 1996 | R | 5,105 | 5,112 | 11,272 | |
| 1992 | R | 4,645 | 4,698 | 12,002 | |
| 1988 | R | 4,860 | 5,394 | 10,305 | |
| 1984 | R | 4,089 | 6,679 | 10,814 | |
| 1980 | R | 3,934 | 5,727 | 10,981 | |
| 1976 | R | 4,685 | 5,278 | 10,026 | |
| 1972 | R | 4,701 | 5,182 | 9,916 | |
| 1968 | R | 3,202 | 4,674 | 8,081 | |
| 1964 | D | 4,191 | 3,692 | 7,883 | |
| 1960 | R | 2,974 | 5,710 | 8,684 | |
| 1956 | R | 2,620 | 5,293 | 7,913 | |
| 1952 | R | 1,861 | 5,988 | 7,849 | |
| 1948 | R | 2,907 | 3,975 | 6,926 | |
| 1944 | R | 2,073 | 4,136 | 6,209 | |
| 1940 | R | 2,671 | 5,016 | 7,687 | |
| 1936 | R | 3,161 | 3,899 | 7,302 | |
| 1932 | D | 3,247 | 3,231 | 6,599 | |
| 1928 | R | 1,915 | 4,586 | 6,547 | |
| 1924 | R | 1,010 | 4,708 | 9,705 | |
| 1920 | R | 564 | 2,743 | 3,996 | |
| 1916 | D | 1,638 | 1,385 | 3,163 | |
| 1912 | D | 740 | 0 | 2,395 | |
| 1908 | R | 588 | 1,697 | 2,669 | |
| 1904 | R | 353 | 2,220 | 2,914 | |
| 1900 | R | 1,084 | 1,707 | 2,976 | |
| 1896 | D | 1,288 | 1,263 | 2,593 | |
| 1892 | R | 189 | 1,082 | 2,098 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Home to South Dakota State University, Brookings County posts presidential margins well below the double-digit spreads typical of surrounding agricultural counties, reflecting the moderating pull of a large student and faculty population.
The county's recent history is a story of close margins. The Democratic margin reached thirty-one points in 1912; the Republican margin reached sixty-four points in 1904. Most other elections have been decided by single-digit points.
Brookings County's demographics — a population of 35,353, a 88% non-Hispanic-white share, a median household income of $70,064 — 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 Yankton County and Codington County.