| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 378 | 1,247 | 1,665 | |
| 2020 | R | 383 | 1,388 | 1,789 | |
| 2016 | R | 320 | 1,216 | 1,702 | |
| 2012 | R | 472 | 1,236 | 1,759 | |
| 2008 | R | 492 | 1,227 | 1,742 | |
| 2004 | R | 411 | 1,454 | 1,881 | |
| 2000 | R | 452 | 1,269 | 1,755 | |
| 1996 | R | 519 | 995 | 1,650 | |
| 1992 | R | 519 | 975 | 1,854 | |
| 1988 | R | 638 | 1,291 | 1,960 | |
| 1984 | R | 488 | 1,503 | 2,019 | |
| 1980 | R | 675 | 1,407 | 2,136 | |
| 1976 | R | 975 | 1,146 | 2,150 | |
| 1972 | R | 496 | 1,545 | 2,131 | |
| 1968 | R | 678 | 1,217 | 2,196 | |
| 1964 | R | 1,159 | 1,232 | 2,401 | |
| 1960 | R | 1,068 | 1,686 | 2,756 | |
| 1956 | R | 1,061 | 1,649 | 2,711 | |
| 1952 | R | 1,142 | 1,988 | 3,136 | |
| 1948 | D | 1,590 | 1,246 | 2,849 | |
| 1944 | R | 1,350 | 1,604 | 2,959 | |
| 1940 | D | 1,987 | 1,900 | 3,899 | |
| 1936 | D | 2,605 | 1,625 | 4,267 | |
| 1932 | D | 3,117 | 1,173 | 4,353 | |
| 1928 | R | 1,306 | 2,081 | 3,400 | |
| 1924 | D | 1,735 | 1,415 | 3,746 | |
| 1920 | R | 2,273 | 2,930 | 5,388 | |
| 1916 | D | 1,996 | 1,495 | 3,749 | |
| 1912 | D | 1,119 | 815 | 2,611 | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
A vast, sparsely settled county on the Oklahoma and Colorado borders, Union delivers lopsided Republican margins in nearly every cycle — its 2024 presidential result of R+52 places it among the state's most one-sided counties.
The Democratic margin in Union County peaked at forty-five points in 1932. By 1952 the county had flipped, voting Republican for the first time in many years. The 2024 margin was fifty-two points, the most Republican-leaning result in the county's modern history.
The economic context is the key. Union County's median household income of $46,694 sits well below state and national norms, and 17% 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 Cheyenne County and Gosper County.