| City | Rank | County | 2026 Pop. ↓ |
|---|---|---|---|
| Twin Falls | 1 | Twin Falls County | 57,077 |
| Jerome | 2 | Jerome County | 14,037 |
| Burley | 3 | Cassia County | 12,548 |
| Hailey | 4 | Blaine County | 10,289 |
| Rupert | 5 | Minidoka County | 6,531 |
| Kimberly | 6 | Twin Falls County | 6,031 |
| Buhl | 7 | Twin Falls County | 4,849 |
| Gooding | 8 | Gooding County | 3,892 |
| Heyburn | 9 | Minidoka County | 3,804 |
| Ketchum | 10 | Blaine County | 3,672 |
| Wendell | 11 | Gooding County | 3,125 |
| Filer | 12 | Twin Falls County | 3,089 |
| Bellevue | 13 | Blaine County | 2,613 |
| Paul | 14 | Minidoka County | 1,853 |
| Shoshone | 15 | Lincoln County | 1,796 |
| Sun Valley | 16 | Blaine County | 1,779 |
| Hansen | 17 | Twin Falls County | 1,114 |
| Hagerman | 18 | Gooding County | 1,001 |
| Oakley | 19 | Cassia County | 847 |
| Hazelton | 20 | Jerome County | 834 |
| Carey | 21 | Blaine County | 732 |
| Richfield | 22 | Lincoln County | 497 |
| Gannett | 23 | Blaine County | 428 |
| Eden | 24 | Jerome County | 409 |
| Declo | 25 | Cassia County | 379 |
| Dietrich | 26 | Lincoln County | 321 |
| Albion | 27 | Cassia County | 271 |
| Hollister | 28 | Jerome County | 270 |
| Bliss | 29 | Gooding County | 265 |
| Castleford | 30 | Twin Falls County | 233 |
| Malta | 31 | Cassia County | 183 |
| Acequia | 32 | Blaine County | 135 |
| Murtaugh | 33 | Twin Falls County | 125 |
| Minidoka | 34 | Minidoka County | 95 |
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.