| Counties | Total Number of Registered Voters at Cutoff | Number Election Day Registrants | Total Number of Registered Voters | Number of Ballots Cast | % of Registered Voters That Voted |
|---|---|---|---|---|---|
| Ada | 179,457 | 2,892 | 182,349 | 38,570 | 21.2% |
| Adams | 2,428 | 198 | 2,626 | 1,373 | 52.3% |
| Bannock | 40,437 | 369 | 40,806 | 7,044 | 17.3% |
| Bear Lake | 3,427 | 63 | 3,490 | 1,547 | 44.3% |
| Benewah | 4,785 | 35 | 4,820 | 1,556 | 32.3% |
| Bingham | 19,667 | 396 | 20,063 | 5,722 | 28.5% |
| Blaine | 11,292 | 145 | 11,437 | 2,043 | 17.9% |
| Boise | 4,235 | 153 | 4,388 | 1,831 | 41.7% |
| Bonner | 20,832 | 299 | 21,131 | 5,835 | 27.6% |
| Bonneville | 43,391 | 587 | 43,978 | 10,094 | 23.0% |
| Boundary | 5,588 | 56 | 5,644 | 1,353 | 24.0% |
| Butte | 1,761 | 43 | 1,804 | 817 | 45.3% |
| Camas | 785 | 12 | 797 | 157 | 19.7% |
| Canyon | 66,762 | 904 | 67,666 | 18,772 | 27.7% |
| Caribou | 4,205 | 37 | 4,242 | 1,517 | 35.8% |
| Cassia | 9,528 | 273 | 9,801 | 3,542 | 36.1% |
| Clark | 378 | 28 | 406 | 355 | 87.4% |
| Clearwater | 4,826 | 21 | 4,847 | 1,129 | 23.3% |
| Custer | 2,726 | 48 | 2,774 | 1,122 | 40.4% |
| Elmore | 9,257 | 109 | 9,366 | 2,174 | 23.2% |
| Franklin | 6,000 | 137 | 6,137 | 2,514 | 41.0% |
| Fremont | 6,390 | 202 | 6,592 | 2,761 | 41.9% |
| Gem | 8,414 | 275 | 8,689 | 2,848 | 32.8% |
| Gooding | 6,320 | 83 | 6,403 | 2,052 | 32.0% |
| Idaho | 9,328 | 129 | 9,457 | 3,491 | 36.9% |
| Jefferson | 10,228 | 161 | 10,389 | 3,315 | 31.9% |
| Jerome | 8,153 | 61 | 8,214 | 2,211 | 26.9% |
| Kootenai | 64,279 | 707 | 64,986 | 15,794 | 24.3% |
| Latah | 20,897 | 136 | 21,033 | 3,544 | 16.8% |
| Lemhi | 5,084 | 25 | 5,109 | 1,709 | 33.5% |
| Lewis | 2,055 | 31 | 2,086 | 878 | 42.1% |
| Lincoln | 2,160 | 55 | 2,215 | 893 | 40.3% |
| Madison | 13,325 | 247 | 13,572 | 3,621 | 26.7% |
| Minidoka | 8,336 | 138 | 8,474 | 1,937 | 22.9% |
| Nez Perce | 20,807 | 93 | 20,900 | 3,546 | 17.0% |
| Oneida | 2,293 | 140 | 2,433 | 1,375 | 56.5% |
| Owyhee | 4,299 | 148 | 4,447 | 1,687 | 37.9% |
| Payette | 9,608 | 131 | 9,739 | 1,976 | 20.3% |
| Power | 3,405 | 15 | 3,420 | 917 | 26.8% |
| Shoshone | 6,868 | 85 | 6,953 | 2,260 | 32.5% |
| Teton | 4,285 | 85 | 4,370 | 1,672 | 38.3% |
| Twin Falls | 34,159 | 353 | 34,512 | 12,534 | 36.3% |
| Valley | 5,696 | 186 | 5,882 | 2,274 | 38.7% |
| Washington | 4,924 | 164 | 5,088 | 2,094 | 41.2% |
| TOTAL | 703,080 | 10,455 | 713,535 | 184,456 | 25.9% |