Voter Registration Totals as of October 1, 2018
| County |
Constitution |
Democratic |
Libertarian |
Republican |
Unaffiliated |
Total Registered |
| Ada |
585 |
42,813 |
2,650 |
102,033 |
91,943 |
240,024 |
| Adams |
15 |
172 |
14 |
1,679 |
658 |
2,538 |
| Bannock |
133 |
4,557 |
385 |
17,267 |
18,417 |
40,759 |
| Bear Lake |
15 |
109 |
7 |
2,577 |
589 |
3,297 |
| Benewah |
27 |
526 |
26 |
2,450 |
2,076 |
5,105 |
| Bingham |
76 |
1,502 |
76 |
12,415 |
5,234 |
19,303 |
| Blaine |
10 |
2,780 |
107 |
3,307 |
6,648 |
12,852 |
| Boise |
24 |
332 |
35 |
2,839 |
1,370 |
4,600 |
| Bonner |
154 |
2,452 |
217 |
14,659 |
7,725 |
25,207 |
| Bonneville |
162 |
3,698 |
373 |
29,448 |
17,242 |
50,923 |
| Boundary |
26 |
431 |
50 |
4,109 |
1,540 |
6,156 |
| Butte |
5 |
57 |
5 |
1,148 |
264 |
1,479 |
| Camas |
5 |
30 |
5 |
454 |
188 |
682 |
| Canyon |
405 |
9,078 |
787 |
45,454 |
31,739 |
87,463 |
| Caribou |
19 |
100 |
11 |
2,680 |
811 |
3,621 |
| Cassia |
29 |
453 |
35 |
6,709 |
2,043 |
9,269 |
| Clark |
2 |
17 |
2 |
312 |
50 |
383 |
| Clearwater |
9 |
371 |
24 |
2,260 |
1,708 |
4,372 |
| Custer |
4 |
140 |
17 |
2,023 |
620 |
2,804 |
| Elmore |
39 |
933 |
75 |
5,902 |
3,248 |
10,197 |
| Franklin |
41 |
167 |
29 |
4,599 |
1,260 |
6,096 |
| Fremont |
29 |
269 |
19 |
5,036 |
1,294 |
6,647 |
| Gem |
42 |
600 |
50 |
6,111 |
2,617 |
9,420 |
| Gooding |
21 |
533 |
35 |
3,750 |
1,790 |
6,129 |
| Idaho |
36 |
542 |
54 |
6,595 |
2,382 |
9,609 |
| Jefferson |
42 |
406 |
49 |
9,948 |
2,867 |
13,312 |
| Jerome |
124 |
662 |
43 |
4,412 |
2,712 |
7,953 |
| Kootenai |
326 |
8,467 |
660 |
43,029 |
26,807 |
79,289 |
| Latah |
86 |
4,296 |
309 |
7,604 |
9,819 |
22,114 |
| Lemhi |
9 |
359 |
25 |
3,197 |
1,180 |
4,770 |
| Lewis |
7 |
157 |
7 |
1,243 |
607 |
2,021 |
| Lincoln |
7 |
163 |
15 |
1,314 |
595 |
2,094 |
| Madison |
84 |
531 |
163 |
12,952 |
4,422 |
18,152 |
| Minidoka |
21 |
527 |
30 |
4,879 |
2,205 |
7,662 |
| Nez Perce |
70 |
2,452 |
122 |
8,583 |
9,893 |
21,120 |
| Oneida |
7 |
92 |
15 |
1,883 |
460 |
2,457 |
| Owyhee |
28 |
357 |
27 |
3,145 |
1,314 |
4,871 |
| Payette |
37 |
882 |
58 |
6,273 |
3,543 |
10,793 |
| Power |
6 |
382 |
12 |
1,697 |
1,172 |
3,269 |
| Shoshone |
21 |
1,356 |
25 |
2,421 |
2,578 |
6,401 |
| Teton |
16 |
1,190 |
50 |
2,421 |
2,415 |
6,092 |
| Twin Falls |
136 |
2,881 |
249 |
19,621 |
11,763 |
34,650 |
| Valley |
15 |
902 |
33 |
3,326 |
2,134 |
6,410 |
| Washington |
8 |
380 |
22 |
3,534 |
1,196 |
5,140 |
| Total |
2,963 |
99,104 |
7,002 |
427,298 |
291,138 |
827,505 |