| County | Election Day Registrants | Total Registered Voters | Ballots Cast | Percentage |
|---|---|---|---|---|
| Ada | 22,023 | 172,224 | 120,739 | 70.1 % |
| Adams | 147 | 2,614 | 2,009 | 76.9 % |
| Bannock | 3,530 | 43,198 | 32,579 | 75.4 % |
| Bear Lake | 191 | 4,017 | 2,914 | 72.5 % |
| Benewah | 386 | 5,117 | 4,064 | 79.4 % |
| Bingham | 1,998 | 20,186 | 15,363 | 76.1 % |
| Blaine | 1,593 | 12,151 | 8,384 | 69.0 % |
| Boise | 414 | 4,087 | 3,052 | 74.7 % |
| Bonner | 1,792 | 18,957 | 15,070 | 79.5 % |
| Bonneville | 4,929 | 46,737 | 34,172 | 73.1 % |
| Boundary | 422 | 5,665 | 4,012 | 70.8 % |
| Butte | 118 | 2,007 | 1,554 | 77.4 % |
| Camas | 26 | 708 | 561 | 79.2 % |
| Canyon | 4,956 | 56,145 | 41,658 | 74.2 % |
| Caribou | 339 | 4,192 | 2,969 | 70.8 % |
| Cassia | 898 | 10,752 | 7,599 | 70.7 % |
| Clark | 18 | 614 | 455 | 74.1 % |
| Clearwater | 424 | 5,508 | 4,051 | 73.5 % |
| Custer | 225 | 3,212 | 2,381 | 74.1 % |
| Elmore | 1,165 | 10,820 | 7,153 | 66.1 % |
| Franklin | 363 | 5,577 | 4,086 | 73.3 % |
| Fremont | 540 | 6,897 | 5,029 | 72.9 % |
| Gem | 945 | 7,710 | 6,468 | 83.9 % |
| Gooding | 481 | 7,603 | 5,416 | 71.2 % |
| Idaho | 684 | 9,977 | 7,389 | 74.1 % |
| Jefferson | 1,013 | 9,863 | 7,620 | 77.3 % |
| Jerome | 563 | 9,085 | 6,531 | 71.9 % |
| Kootenai | 4,108 | 58,570 | 40,679 | 69.5 % |
| Latah | 3,584 | 22,501 | 16,918 | 75.2 % |
| Lemhi | 242 | 4,922 | 3,954 | 80.3 % |
| Lewis | 200 | 2,538 | 1,945 | 76.6 % |
| Lincoln | 135 | 2,280 | 1,625 | 71.3 % |
| Madison | 1,660 | 11,392 | 8,007 | 70.3 % |
| Minidoka | 655 | 9,927 | 7,325 | 73.8 % |
| Nez Perce | 1,183 | 23,325 | 17,268 | 74.0 % |
| Oneida | 138 | 2,501 | 1,781 | 71.2 % |
| Owyhee | 541 | 4,960 | 3,439 | 69.3 % |
| Payette | 1,193 | 10,442 | 7,292 | 69.8 % |
| Power | 223 | 4,063 | 3,033 | 74.6 % |
| Shoshone | 658 | 8,499 | 6,200 | 72.9 % |
| Teton | 254 | 3,515 | 2,581 | 73.4 % |
| Twin Falls | 2,257 | 34,258 | 23,953 | 69.9 % |
| Valley | 467 | 5,811 | 4,419 | 76.0 % |
| Washington | 383 | 5,303 | 4,333 | 81.7 % |
| Total | 68,064 | 700,430 | 508,030 | 72.5 % |
| 1st Cong. Dist | 36,964 | 372,427 | 266,355 | 71.5 % |
| 2nd Cong. Dist | 30,604 | 325,776 | 232,689 | 71.4 % |