| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 2,767 | 13,925 | 17,358 | |
| 2020 | R | 2,666 | 13,559 | 17,112 | |
| 2016 | R | 1,201 | 8,941 | 15,687 | |
| 2012 | R | 832 | 13,445 | 14,412 | |
| 2008 | R | 1,627 | 11,131 | 13,057 | |
| 2004 | R | 826 | 10,693 | 11,637 | |
| 2000 | R | 816 | 7,941 | 8,970 | |
| 1996 | R | 1,216 | 5,706 | 7,728 | |
| 1992 | R | 741 | 4,591 | 7,763 | |
| 1988 | R | 1,009 | 6,197 | 7,302 | |
| 1984 | R | 483 | 6,798 | 7,319 | |
| 1980 | R | 728 | 6,555 | 7,414 | |
| 1976 | R | 1,320 | 4,190 | 5,789 | |
| 1972 | R | 710 | 3,606 | 5,216 | |
| 1968 | R | 904 | 2,971 | 4,388 | |
| 1964 | R | 1,949 | 2,101 | 4,050 | |
| 1960 | R | 1,678 | 2,374 | 4,052 | |
| 1956 | R | 1,423 | 2,538 | 3,961 | |
| 1952 | R | 1,348 | 2,756 | 4,106 | |
| 1948 | D | 2,024 | 1,602 | 3,647 | |
| 1944 | D | 1,927 | 1,527 | 3,458 | |
| 1940 | D | 2,218 | 1,632 | 3,851 | |
| 1936 | D | 2,455 | 1,114 | 3,592 | |
| 1932 | D | 2,112 | 1,272 | 3,407 | |
| 1928 | R | 1,228 | 1,670 | 2,900 | |
| 1924 | R | 601 | 1,417 | 2,633 | |
| 1920 | R | 979 | 1,883 | 2,862 | |
| 1916 | D | 1,371 | 1,132 | 2,524 | |
| 1912 | — | — | — | — | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Madison County's dominant Latter-day Saint population and university town of Rexburg produce presidential margins that routinely rank among the highest in Idaho, with the 2024 result of R+64.8 reflecting deep, consistent partisan alignment.
The Democratic margin in Madison County peaked at thirty-seven points in 1936. By 1952 the county had flipped, voting Republican for the first time in many years. The 2024 margin was sixty-four points, the most Republican-leaning result in the county's modern history.
The economic context is the key. Madison County's median household income of $60,160 sits well below state and national norms, and 25% 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 Iron County and Garfield County.