| City | Rank | County | 2026 Pop. ↓ |
|---|---|---|---|
| Twin Falls | 1 | Twin Falls County | 57,325 |
| Jerome | 2 | Jerome County | 14,039 |
| Burley | 3 | Cassia County | 12,435 |
| Hailey | 4 | Blaine County | 10,362 |
| Rupert | 5 | Minidoka County | 6,483 |
| Kimberly | 6 | Twin Falls County | 6,061 |
| Buhl | 7 | Twin Falls County | 4,856 |
| Gooding | 8 | Gooding County | 3,877 |
| Heyburn | 9 | Minidoka County | 3,781 |
| Ketchum | 10 | Blaine County | 3,634 |
| Filer | 11 | Twin Falls County | 3,166 |
| Wendell | 12 | Gooding County | 3,084 |
| Bellevue | 13 | Blaine County | 2,591 |
| Paul | 14 | Minidoka County | 1,984 |
| Shoshone | 15 | Lincoln County | 1,805 |
| Sun Valley | 16 | Blaine County | 1,761 |
| Hansen | 17 | Twin Falls County | 1,131 |
| Hagerman | 18 | Gooding County | 1,000 |
| Oakley | 19 | Cassia County | 853 |
| Hazelton | 20 | Jerome County | 839 |
| Carey | 21 | Blaine County | 709 |
| Richfield | 22 | Lincoln County | 500 |
| Gannett | 23 | Blaine County | 428 |
| Eden | 24 | Jerome County | 411 |
| Declo | 25 | Cassia County | 375 |
| Dietrich | 26 | Lincoln County | 324 |
| Hollister | 27 | Jerome County | 279 |
| Bliss | 28 | Gooding County | 269 |
| Albion | 29 | Cassia County | 264 |
| Castleford | 30 | Twin Falls County | 232 |
| Malta | 31 | Cassia County | 184 |
| Acequia | 32 | Blaine County | 139 |
| Murtaugh | 33 | Twin Falls County | 127 |
| Minidoka | 34 | Minidoka County | 84 |
Twin Falls County, Cassia County, Jerome County, Blaine County, Minidoka County, Gooding County, and Lincoln County are the counties generally considered part of South Idaho.