| County | Election Day Registrants | Total Registered Voters | Ballots Cast | Percentage |
|---|---|---|---|---|
| Ada | 12,425 | 146,661 | 98,099 | 66.9 % |
| Adams | 106 | 2,471 | 1,757 | 71.1 % |
| Bannock | 1,664 | 39,762 | 27,699 | 69.7 % |
| Bear Lake | 61 | 3,697 | 2,519 | 68.1 % |
| Benewah | 87 | 4,630 | 2,918 | 63.0 % |
| Bingham | 660 | 20,128 | 13,740 | 68.3 % |
| Blaine | 309 | 10,231 | 6,777 | 66.2 % |
| Boise | 176 | 3,515 | 2,401 | 68.3 % |
| Bonner | 676 | 17,692 | 11,729 | 66.3 % |
| Bonneville | 1,371 | 42,413 | 29,153 | 68.7 % |
| Boundary | 165 | 4,956 | 3,248 | 65.5 % |
| Butte | 42 | 1,813 | 1,296 | 71.5 % |
| Camas | 19 | 611 | 496 | 81.2 % |
| Canyon | 2,424 | 48,813 | 34,843 | 71.4 % |
| Caribou | 176 | 3,895 | 2,895 | 74.3 % |
| Cassia | 534 | 9,493 | 6,692 | 70.5 % |
| Clark | 27 | 539 | 396 | 73.5 % |
| Clearwater | 178 | 5,129 | 3,410 | 66.5 % |
| Custer | 143 | 2,734 | 1,816 | 66.4 % |
| Elmore | 387 | 8,929 | 5,675 | 63.6 % |
| Franklin | 162 | 5,537 | 3,698 | 66.8 % |
| Fremont | 237 | 6,126 | 4,486 | 73.2 % |
| Gem | 452 | 7,566 | 5,525 | 73.0 % |
| Gooding | 298 | 6,928 | 4,982 | 71.9 % |
| Idaho | 314 | 8,722 | 6,215 | 71.3 % |
| Jefferson | 465 | 9,413 | 6,616 | 70.3 % |
| Jerome | 319 | 8,198 | 5,316 | 64.8 % |
| Kootenai | 1,432 | 48,673 | 30,281 | 62.2 % |
| Latah | 988 | 21,953 | 13,371 | 60.9 % |
| Lemhi | 121 | 4,693 | 3,191 | 68.0 % |
| Lewis | 114 | 2,331 | 1,595 | 68.4 % |
| Lincoln | 83 | 2,088 | 1,555 | 74.5 % |
| Madison | 570 | 10,214 | 6,706 | 65.7 % |
| Minidoka | 287 | 9,040 | 6,395 | 70.7 % |
| Nez Perce | 610 | 21,510 | 14,501 | 67.4 % |
| Oneida | 50 | 2,214 | 1,572 | 71.0 % |
| Owyhee | 293 | 4,297 | 2,951 | 68.7 % |
| Payette | 504 | 9,222 | 6,019 | 65.3 % |
| Power | 172 | 3,850 | 2,607 | 67.7 % |
| Shoshone | 178 | 8,344 | 5,175 | 62.0 % |
| Teton | 247 | 2,636 | 1,998 | 75.8 % |
| Twin Falls | 1,819 | 33,332 | 19,555 | 58.7 % |
| Valley | 193 | 5,477 | 3,674 | 67.1 % |
| Washington | 166 | 5,327 | 3,787 | 71.1 % |
| Total | 31,704 | 625,803 | 419,330 | 67.0 % |
| 1st Cong. Dist. | 327,358 | 218,443 | 66.7 % |
| 2nd Cong. Dist. | 298,445 | 200,887 | 67.3 % |