| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 122 | 546 | 688 | |
| 2020 | R | 126 | 603 | 744 | |
| 2016 | R | 100 | 556 | 689 | |
| 2012 | R | 167 | 520 | 703 | |
| 2008 | R | 211 | 503 | 735 | |
| 2004 | R | 181 | 546 | 736 | |
| 2000 | R | 164 | 541 | 746 | |
| 1996 | R | 259 | 417 | 780 | |
| 1992 | R | 260 | 412 | 856 | |
| 1988 | R | 343 | 541 | 900 | |
| 1984 | R | 289 | 693 | 991 | |
| 1980 | R | 283 | 580 | 927 | |
| 1976 | R | 415 | 597 | 1,019 | |
| 1972 | R | 303 | 685 | 999 | |
| 1968 | R | 270 | 635 | 937 | |
| 1964 | R | 488 | 555 | 1,048 | |
| 1960 | R | 338 | 649 | 987 | |
| 1956 | R | 403 | 637 | 1,040 | |
| 1952 | R | 338 | 771 | 1,114 | |
| 1948 | D | 527 | 499 | 1,042 | |
| 1944 | R | 468 | 598 | 1,074 | |
| 1940 | R | 554 | 597 | 1,161 | |
| 1936 | D | 877 | 454 | 1,363 | |
| 1932 | D | 732 | 634 | 1,387 | |
| 1928 | R | 405 | 968 | 1,379 | |
| 1924 | R | 162 | 683 | 1,215 | |
| 1920 | R | 242 | 881 | 1,149 | |
| 1916 | D | 622 | 535 | 1,179 | |
| 1912 | — | — | — | — | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Prairie County's roughly 1,200 residents are spread across 1,700 square miles of eastern Montana rangeland, and its presidential margins have exceeded R+60 in recent cycles, making it a reliable anchor of the state's deep-red eastern bloc.
The Democratic margin in Prairie County peaked at thirty-one points in 1936. By 1952 the county had flipped, voting Republican for the first time in many years. The 2024 margin was sixty-two points, the most Republican-leaning result in the county's modern history.
The economic context is the key. Prairie County's median household income of $51,250 sits well below state and national norms, and 21% 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 Fallon County and Lincoln County.