| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 69,653 | 106,133 | 178,513 | |
| 2020 | R | 64,705 | 100,913 | 168,713 | |
| 2016 | R | 44,973 | 88,467 | 143,848 | |
| 2012 | R | 42,737 | 88,166 | 132,757 | |
| 2008 | R | 50,828 | 83,330 | 136,268 | |
| 2004 | R | 35,552 | 92,048 | 128,643 | |
| 2000 | R | 29,600 | 78,703 | 110,599 | |
| 1996 | R | 27,024 | 61,436 | 95,416 | |
| 1992 | R | 22,180 | 56,862 | 96,211 | |
| 1988 | R | 18,769 | 61,515 | 80,729 | |
| 1984 | R | 15,000 | 60,142 | 75,468 | |
| 1980 | R | 18,435 | 51,217 | 75,484 | |
| 1976 | R | 16,381 | 49,196 | 66,370 | |
| 1972 | R | 15,119 | 42,169 | 58,576 | |
| 1968 | R | 12,431 | 33,356 | 49,342 | |
| 1964 | R | 20,151 | 24,512 | 44,735 | |
| 1960 | R | 10,617 | 32,678 | 43,423 | |
| 1956 | R | 9,459 | 28,611 | 38,200 | |
| 1952 | R | 7,835 | 22,328 | 30,657 | |
| 1948 | R | 8,789 | 16,028 | 25,288 | |
| 1944 | R | 8,511 | 17,077 | 25,786 | |
| 1940 | R | 9,152 | 15,462 | 24,784 | |
| 1936 | R | 9,579 | 11,114 | 21,645 | |
| 1932 | R | 7,981 | 12,076 | 20,700 | |
| 1928 | R | 2,524 | 15,417 | 18,035 | |
| 1924 | R | 1,871 | 11,688 | 14,880 | |
| 1920 | R | 2,391 | 10,528 | 13,370 | |
| 1916 | R | 3,941 | 5,484 | 9,760 | |
| 1912 | D | 2,036 | 1,825 | 8,746 | |
| 1908 | R | 2,429 | 5,642 | 8,516 | |
| 1904 | R | 1,553 | 5,908 | 7,843 | |
| 1900 | R | 3,050 | 5,324 | 8,558 | |
| 1896 | R | 3,550 | 5,188 | 8,937 | |
| 1892 | R | 2,996 | 3,643 | 7,169 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Ottawa County's Dutch Reformed heritage and suburban-rural mix have anchored it among Michigan's most reliably Republican counties for decades, with the 2024 presidential margin landing at R+20.4 despite modest population growth drawing in new residents.
The Republican margin in Ottawa County reached its widest at seventy-one points in 1928. The margin in 2024 was twenty points, in line with the county's deep historical pattern.
Ottawa County's loyalty is rooted in its place. Median household income of $90,502, a 84% non-Hispanic-white share, and a population of 301,203 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 Hendricks County and Cumberland County.