| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 2,688 | 7,699 | 10,523 | |
| 2020 | R | 2,704 | 7,732 | 10,666 | |
| 2016 | R | 2,570 | 6,981 | 10,133 | |
| 2012 | R | 3,539 | 6,186 | 9,982 | |
| 2008 | R | 4,434 | 6,167 | 10,781 | |
| 2004 | R | 4,318 | 6,294 | 10,683 | |
| 2000 | R | 4,551 | 5,256 | 9,985 | |
| 1996 | D | 4,690 | 3,955 | 9,778 | |
| 1992 | D | 4,731 | 3,798 | 10,654 | |
| 1988 | D | 5,226 | 5,072 | 10,327 | |
| 1984 | R | 4,662 | 7,261 | 11,923 | |
| 1980 | R | 5,168 | 6,347 | 11,834 | |
| 1976 | D | 5,600 | 5,378 | 11,032 | |
| 1972 | R | 3,706 | 7,197 | 10,903 | |
| 1968 | R | 4,806 | 5,005 | 10,823 | |
| 1964 | D | 7,387 | 3,316 | 10,703 | |
| 1960 | D | 6,410 | 4,955 | 11,365 | |
| 1956 | D | 5,951 | 4,664 | 10,615 | |
| 1952 | D | 6,775 | 4,767 | 11,554 | |
| 1948 | D | 7,495 | 2,739 | 10,250 | |
| 1944 | D | 6,471 | 3,455 | 9,939 | |
| 1940 | D | 7,768 | 3,447 | 11,224 | |
| 1936 | D | 7,455 | 2,508 | 9,994 | |
| 1932 | D | 7,301 | 2,037 | 9,392 | |
| 1928 | D | 5,067 | 4,141 | 9,222 | |
| 1924 | D | 5,866 | 3,125 | 9,142 | |
| 1920 | D | 5,514 | 3,827 | 9,409 | |
| 1916 | D | 3,572 | 1,741 | 5,361 | |
| 1912 | D | 3,332 | 1,360 | 5,143 | |
| 1908 | D | 3,350 | 1,733 | 5,156 | |
| 1904 | D | 3,006 | 1,454 | 4,571 | |
| 1900 | D | 3,477 | 1,436 | 5,024 | |
| 1896 | D | 3,984 | 1,609 | 5,628 | |
| 1892 | D | 3,240 | 1,408 | 4,908 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Audrain County, anchored by Mexico, Mo., has shifted decisively rightward over the past four election cycles, posting a 47-point Republican presidential margin in 2024 — a gap that reflects broader rural realignment across the Little Dixie region.
The unraveling was not abrupt. The Democratic margin in Audrain County peaked at fifty-six points in 1932; it narrowed steadily over the late twentieth century. The 2000 election delivered the county to the Republican party for the first time in many years, by a margin of seven points. By 2024, the margin had widened further.
The economic and demographic context is severe. Audrain County's median household income of $59,448 is among the lowest of any county in the United States; 18% of residents live below the federal poverty line. The county's voting pattern over the last decade is most similar to that of Wayne County and Taylor County.