| Region 5 | ||||||||
| Number of Registered Voters | ||||||||
| Source: Office of the Secretary of State | ||||||||
| 1994 | 1996 | 1998 | 2000 | 2002 | 2004 | 2006 | 2008 | |
| Blaine | 10,231 | 12,151 | 10,520 | 11,436 | 10,244 | 12,612 | 11,700 | 13,988 |
| Camas | 611 | 708 | 662 | 703 | 724 | 858 | 870 | 837 |
| Cassia | 9,493 | 10,752 | 10,032 | 10,495 | 9,671 | 10,238 | 10,080 | 10,385 |
| Gooding | 6,928 | 7,603 | 7,053 | 7,579 | 6,557 | 7,219 | 6,690 | 6,818 |
| Jerome | 8,198 | 9,085 | 8,532 | 9,449 | 8,403 | 8,786 | 8,528 | 10,098 |
| Lincoln | 2,088 | 2,280 | 2,093 | 2,047 | 1,882 | 2,294 | 2,285 | 2,471 |
| Minidoka | 9,040 | 9,927 | 9,118 | 9,585 | 8,693 | 9,515 | 8,723 | 9,409 |
| Twin Falls | 33,332 | 34,258 | 30,378 | 32,427 | 29,605 | 35,488 | 35,756 | 37,680 |
| * Population 18 years and over | ||||||||
| * This data is for the general elections of the reported years. | ||||||||