| Counties | Total Number of Registered Voters at Cutoff | Number Election Day Registrants | Total Number Registered Voters | Number Ballots Cast | % of Registered Voters That Voted |
|---|---|---|---|---|---|
| Ada | 184,483 | 2,562 | 187,045 | 39,518 | 21.13% |
| Adams | 2,535 | 103 | 2,638 | 1,347 | 51.06% |
| Bannock | 38,839 | 395 | 39,234 | 7,012 | 17.87% |
| Bear Lake | 3,398 | 81 | 3,479 | 1,663 | 47.80% |
| Benewah | 4,727 | 28 | 4,755 | 1,247 | 26.23% |
| Bingham | 19,479 | 441 | 19,920 | 6,702 | 33.64% |
| Blaine | 11,489 | 136 | 11,625 | 2,475 | 21.29% |
| Boise | 4,580 | 129 | 4,709 | 1,920 | 40.77% |
| Bonner | 22,041 | 331 | 22,372 | 6,842 | 30.58% |
| Bonneville | 43,865 | 568 | 44,433 | 7,863 | 17.70% |
| Boundary | 5,364 | 116 | 5,480 | 2,074 | 37.85% |
| Butte | 1,600 | 117 | 1,717 | 1,022 | 59.52% |
| Camas | 725 | 38 | 763 | 374 | 49.02% |
| Canyon | 68,170 | 847 | 69,017 | 19,038 | 27.58% |
| Caribou | 3,952 | 162 | 4,114 | 2,288 | 55.61% |
| Cassia | 8,647 | 244 | 8,891 | 3,377 | 37.98% |
| Clark | 386 | 17 | 403 | 289 | 71.71% |
| Clearwater | 4,577 | 32 | 4,609 | 1,045 | 22.67% |
| Custer | 2,715 | 54 | 2,769 | 1,163 | 42.00% |
| Elmore | 9,643 | 124 | 9,767 | 2,435 | 24.93% |
| Franklin | 5,986 | 109 | 6,095 | 2,386 | 39.15% |
| Fremont | 6,612 | 277 | 6,889 | 3,462 | 50.25% |
| Gem | 8,583 | 282 | 8,865 | 3,467 | 39.11% |
| Gooding | 6,449 | 93 | 6,542 | 2,346 | 35.86% |
| Idaho | 9,834 | 183 | 10,017 | 3,657 | 36.51% |
| Jefferson | 10,927 | 88 | 11,015 | 2,002 | 18.18% |
| Jerome | 8,065 | 142 | 8,207 | 2,575 | 31.38% |
| Kootenai | 66,297 | 528 | 66,825 | 14,171 | 21.21% |
| Latah | 20,868 | 82 | 20,950 | 2,406 | 11.48% |
| Lemhi | 4,856 | 65 | 4,921 | 2,164 | 43.97% |
| Lewis | 2,050 | 42 | 2,092 | 900 | 43.02% |
| Lincoln | 2,092 | 71 | 2,163 | 982 | 45.40% |
| Madison | 13,708 | 331 | 14,039 | 4,498 | 32.04% |
| Minidoka | 8,211 | 101 | 8,312 | 2,303 | 27.71% |
| Nez Perce | 20,719 | 158 | 20,877 | 3,827 | 18.33% |
| Oneida | 2,493 | 111 | 2,604 | 1,531 | 58.79% |
| Owyhee | 4,360 | 197 | 4,557 | 2,049 | 44.96% |
| Payette | 10,040 | 92 | 10,132 | 2,023 | 19.97% |
| Power | 3,258 | 19 | 3,277 | 588 | 17.94% |
| Shoshone | 6,062 | 234 | 6,296 | 3,317 | 52.68% |
| Teton | 5,120 | 44 | 5,164 | 1,456 | 28.20% |
| Twin Falls | 32,259 | 191 | 32,450 | 6,218 | 19.16% |
| Valley | 5,982 | 191 | 6,173 | 2,351 | 38.09% |
| Washington | 4,889 | 178 | 5,067 | 2,254 | 44.48% |
| TOTAL | 710,935 | 10,334 | 721,269 | 182,627 | 25.32% |