| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 471 | 2,422 | 2,943 | |
| 2020 | R | 506 | 2,610 | 3,191 | |
| 2016 | R | 424 | 2,283 | 2,924 | |
| 2012 | R | 558 | 2,295 | 2,933 | |
| 2008 | R | 704 | 2,323 | 3,086 | |
| 2004 | R | 595 | 2,333 | 2,971 | |
| 2000 | R | 631 | 1,977 | 2,791 | |
| 1996 | R | 752 | 1,846 | 2,890 | |
| 1992 | R | 764 | 1,284 | 2,820 | |
| 1988 | R | 953 | 1,836 | 2,834 | |
| 1984 | R | 699 | 2,345 | 3,096 | |
| 1980 | R | 630 | 2,118 | 2,947 | |
| 1976 | R | 1,393 | 1,629 | 3,082 | |
| 1972 | R | 705 | 2,065 | 2,831 | |
| 1968 | R | 777 | 1,740 | 2,777 | |
| 1964 | D | 1,535 | 1,491 | 3,052 | |
| 1960 | R | 1,072 | 2,190 | 3,278 | |
| 1956 | R | 1,037 | 2,329 | 3,385 | |
| 1952 | R | 801 | 2,916 | 3,755 | |
| 1948 | R | 1,424 | 2,203 | 3,734 | |
| 1944 | R | 1,378 | 2,428 | 3,847 | |
| 1940 | R | 2,065 | 2,810 | 4,925 | |
| 1936 | D | 2,785 | 2,230 | 5,033 | |
| 1932 | D | 2,505 | 1,884 | 4,559 | |
| 1928 | R | 1,131 | 3,158 | 4,354 | |
| 1924 | R | 854 | 2,475 | 4,108 | |
| 1920 | R | 1,358 | 2,512 | 3,991 | |
| 1916 | D | 2,711 | 2,013 | 4,964 | |
| 1912 | D | 1,264 | 517 | 2,829 | |
| 1908 | R | 1,265 | 1,444 | 2,857 | |
| 1904 | R | 477 | 1,682 | 2,538 | |
| 1900 | R | 1,367 | 1,509 | 2,924 | |
| 1896 | D | 1,486 | 1,256 | 2,773 | |
| 1892 | R | 0 | 1,541 | 3,041 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Ottawa County's rural, sparsely populated plains have produced Republican presidential margins above 60 points in recent cycles, making it among the most reliably one-sided counties in a state already tilted heavily toward GOP candidates at the federal level.
The Republican margin in Ottawa County reached its widest at sixty-six points in 2024. The margin in 2024 was sixty-six points, in line with the county's deep historical pattern.
Ottawa County's loyalty is rooted in its place. Median household income of $74,018, a 94% non-Hispanic-white share, and a population of 5,819 together describe a community whose political habits are deeply settled. The county's voting pattern over the last decade is most similar to that of Wabaunsee County and Dickinson County.