Idaho Counties by Population (2026)
2026 Pop.
50K
100K
150K
200K
250K
300K
350K
400K
450K
500K
550K
Top 5 Most Populous Counties
557,057
282,802
195,330
137,749
98,611
| County | 2026 Pop. ↓ | Area (mi²) | Density (/mi²) | Change (2020) |
|---|---|---|---|---|
| Ada County | 557,057 | 1.1K | 530 | 11.8% |
| Canyon County | 282,802 | 587 | 482 | 21.37% |
| Kootenai County | 195,330 | 1.2K | 158 | 13.04% |
| Bonneville County | 137,749 | 1.9K | 74 | 10.44% |
| Twin Falls County | 98,611 | 1.9K | 51 | 9.13% |
| Bannock County | 92,213 | 1.1K | 83 | 5.63% |
| Madison County | 55,396 | 469 | 118 | 4.62% |
| Bonner County | 55,190 | 1.7K | 32 | 16.41% |
| Bingham County | 51,340 | 2.1K | 25 | 6.74% |
| Nez Perce County | 42,916 | 848 | 51 | 1.82% |
| Latah County | 41,946 | 1.1K | 39 | 5.84% |
| Jefferson County | 35,738 | 1.1K | 33 | 14.99% |
| Elmore County | 29,355 | 3.1K | 9.5 | 2.39% |
| Payette County | 27,969 | 407 | 69 | 9.35% |
| Cassia County | 26,584 | 2.6K | 10 | 7.4% |
| Jerome County | 26,436 | 598 | 44 | 8.93% |
| Blaine County | 25,333 | 2.6K | 9.6 | 4.08% |
| Minidoka County | 23,095 | 757 | 31 | 6.58% |
| Gem County | 22,096 | 560 | 39 | 14.64% |
| Idaho County | 17,875 | 8.5K | 2.1 | 7.73% |
| Gooding County | 16,493 | 729 | 23 | 5.41% |
| Franklin County | 16,116 | 663 | 24 | 12.83% |
| Shoshone County | 14,234 | 2.6K | 5.4 | 7.85% |
| Boundary County | 14,138 | 1.3K | 11 | 16.45% |
| Fremont County | 14,070 | 1.9K | 7.5 | 4.84% |
| Teton County | 13,403 | 449 | 30 | 14.17% |
| Valley County | 12,845 | 3.7K | 3.5 | 8.48% |
| Owyhee County | 12,558 | 7.7K | 1.6 | 4.71% |
| Washington County | 11,674 | 1.5K | 8.0 | 10.59% |
| Benewah County | 10,530 | 777 | 14 | 9.92% |
| Clearwater County | 9,087 | 2.5K | 3.7 | 3.76% |
| Boise County | 8,584 | 1.9K | 4.5 | 12.03% |
| Lemhi County | 8,540 | 4.6K | 1.9 | 7.35% |
| Power County | 8,159 | 1.4K | 5.8 | 3.54% |
| Caribou County | 7,282 | 1.8K | 4.1 | 3.84% |
| Bear Lake County | 6,751 | 976 | 6.9 | 6.06% |
| Lincoln County | 5,575 | 1.2K | 4.6 | 8.53% |
| Oneida County | 5,154 | 1.2K | 4.3 | 12.93% |
| Adams County | 5,016 | 1.4K | 3.7 | 13.41% |
| Custer County | 4,690 | 4.9K | 0.95 | 9.86% |
| Lewis County | 3,695 | 479 | 7.7 | 4.56% |
| Butte County | 2,840 | 2.2K | 1.3 | 10.03% |
| Camas County | 1,345 | 1.1K | 1.3 | 24.42% |
| Clark County | 784 | 1.8K | 0.44 | -0.88% |
Sources
- US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
- US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
- American Community Survey (2009 - 2013)
- Census QuickFacts
- Historical Populations of States and Counties (1790 - 1990)