| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 3,046 | 10,670 | 13,998 | |
| 2020 | R | 3,235 | 10,925 | 14,473 | |
| 2016 | R | 2,766 | 9,975 | 13,601 | |
| 2012 | R | 4,222 | 8,174 | 12,813 | |
| 2008 | R | 5,564 | 8,312 | 14,113 | |
| 2004 | R | 3,886 | 9,600 | 13,628 | |
| 2000 | R | 4,155 | 8,401 | 12,928 | |
| 1996 | R | 4,260 | 6,719 | 12,760 | |
| 1992 | R | 3,967 | 6,416 | 13,918 | |
| 1988 | R | 4,613 | 8,533 | 13,236 | |
| 1984 | R | 4,224 | 9,551 | 13,892 | |
| 1980 | R | 4,927 | 8,672 | 14,304 | |
| 1976 | R | 6,257 | 8,263 | 15,155 | |
| 1972 | R | 3,889 | 9,477 | 13,450 | |
| 1968 | R | 5,019 | 7,295 | 13,655 | |
| 1964 | D | 7,667 | 6,270 | 14,060 | |
| 1960 | R | 6,191 | 8,844 | 15,131 | |
| 1956 | R | 5,724 | 9,574 | 15,372 | |
| 1952 | R | 6,264 | 9,254 | 15,694 | |
| 1948 | R | 6,538 | 7,083 | 13,863 | |
| 1944 | R | 6,379 | 8,207 | 14,777 | |
| 1940 | R | 7,252 | 8,217 | 15,575 | |
| 1936 | D | 8,173 | 6,747 | 15,122 | |
| 1932 | D | 8,892 | 5,987 | 15,191 | |
| 1928 | R | 5,592 | 8,318 | 14,052 | |
| 1924 | R | 4,976 | 6,796 | 13,199 | |
| 1920 | R | 6,259 | 7,336 | 14,124 | |
| 1916 | D | 3,854 | 3,390 | 7,854 | |
| 1912 | D | 3,366 | 1,426 | 7,494 | |
| 1908 | D | 4,176 | 3,820 | 8,440 | |
| 1904 | R | 3,605 | 4,124 | 8,327 | |
| 1900 | D | 3,849 | 3,812 | 7,904 | |
| 1896 | D | 3,602 | 3,393 | 7,140 | |
| 1892 | D | 3,433 | 2,974 | 6,714 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Miami County, anchored by the small city of Peru, delivers lopsided Republican margins in nearly every cycle — its 2024 presidential result of R+54.5 reflects a broader shift toward single-party dominance across rural north-central Indiana.
The Democratic margin in Miami County peaked at twenty-six points in 1912. By 1968 the county had flipped, voting Republican for the first time in many years. The 2024 margin was fifty-four points, the most Republican-leaning result in the county's modern history.
The economic context is the key. Miami County's median household income of $61,139 sits well below state and national norms, and 15% 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 Lawrence County and Jasper County.