| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 14,306 | 24,329 | 39,971 | |
| 2020 | R | 14,682 | 23,331 | 39,783 | |
| 2016 | R | 10,342 | 17,180 | 33,405 | |
| 2012 | R | 13,214 | 21,010 | 35,260 | |
| 2008 | R | 14,792 | 19,356 | 35,105 | |
| 2004 | R | 12,903 | 21,479 | 34,844 | |
| 2000 | R | 10,892 | 18,223 | 30,852 | |
| 1996 | R | 12,806 | 14,058 | 31,377 | |
| 1992 | R | 11,091 | 12,016 | 32,211 | |
| 1988 | R | 13,074 | 14,986 | 28,601 | |
| 1984 | R | 9,399 | 18,742 | 28,496 | |
| 1980 | R | 8,639 | 18,477 | 29,859 | |
| 1976 | R | 10,261 | 13,172 | 24,550 | |
| 1972 | R | 7,840 | 12,856 | 22,191 | |
| 1968 | R | 9,084 | 10,234 | 21,334 | |
| 1964 | D | 13,483 | 7,825 | 21,308 | |
| 1960 | D | 12,586 | 9,157 | 21,743 | |
| 1956 | R | 9,101 | 10,476 | 19,577 | |
| 1952 | R | 8,771 | 10,864 | 19,662 | |
| 1948 | D | 9,679 | 5,580 | 15,560 | |
| 1944 | D | 9,681 | 5,413 | 15,105 | |
| 1940 | D | 10,493 | 5,419 | 15,913 | |
| 1936 | D | 9,443 | 3,830 | 13,393 | |
| 1932 | D | 8,271 | 4,676 | 13,059 | |
| 1928 | R | 4,602 | 5,297 | 9,953 | |
| 1924 | R | 1,612 | 4,520 | 10,046 | |
| 1920 | R | 2,986 | 4,871 | 7,857 | |
| 1916 | D | 4,084 | 2,950 | 7,356 | |
| 1912 | R | 1,486 | 2,316 | 4,821 | |
| 1908 | R | 1,892 | 2,690 | 4,740 | |
| 1904 | R | 1,063 | 2,826 | 4,121 | |
| 1900 | R | 1,581 | 1,684 | 3,295 | |
| 1896 | D | 1,363 | 228 | 1,598 | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Bannock County runs notably closer in statewide contests than its neighbors, anchored by Pocatello's university population and union-era labor heritage, which consistently trims Republican margins to the mid-twenties even as surrounding counties run 40–50 points redder.
The Republican margin in Bannock County reached its widest at forty-three points in 1904. The margin in 2024 was twenty-five points, in line with the county's deep historical pattern.
Bannock County's loyalty is rooted in its place. Median household income of $66,499, a 83% non-Hispanic-white share, and a population of 89,454 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 Jefferson County and Umatilla County.