| City | County | 2026 Pop. ↓ |
|---|---|---|
| Boise City | Ada County | 238,853 |
| Blackfoot | Bingham County | 13,566 |
| Burley | Cassia County | 12,548 |
| Buhl | Twin Falls County | 4,849 |
| Bonners Ferry | Boundary County | 2,849 |
| Bellevue | Blaine County | 2,613 |
| Blanchard | Bonner County | 709 |
| Basalt | Bingham County | 380 |
| Bancroft | Caribou County | 321 |
| Bliss | Gooding County | 265 |
| Bloomington | Bear Lake County | 216 |
| Bovill | Latah County | 197 |
| Bennington | Bear Lake County | 104 |
| Butte City | Butte County | 88 |
| Bruneau | Owyhee County | 44 |