34 cities
| City | Rank | County | 2025 Pop. ↓ |
|---|---|---|---|
| Twin Falls | 1 | Twin Falls County | 56,849 |
| Jerome | 2 | Jerome County | 13,641 |
| Burley | 3 | Cassia County | 12,404 |
| Hailey | 4 | Blaine County | 10,234 |
| Rupert | 5 | Minidoka County | 6,470 |
| Kimberly | 6 | Twin Falls County | 5,831 |
| Buhl | 7 | Twin Falls County | 4,813 |
| Gooding | 8 | Gooding County | 3,859 |
| Heyburn | 9 | Minidoka County | 3,741 |
| Ketchum | 10 | Blaine County | 3,644 |
| Filer | 11 | Twin Falls County | 3,079 |
| Wendell | 12 | Gooding County | 3,066 |
| Bellevue | 13 | Blaine County | 2,582 |
| Paul | 14 | Minidoka County | 2,076 |
| Shoshone | 15 | Lincoln County | 1,770 |
| Sun Valley | 16 | Blaine County | 1,757 |
| Hansen | 17 | Twin Falls County | 1,127 |
| Hagerman | 18 | Gooding County | 1,000 |
| Oakley | 19 | Cassia County | 835 |
| Hazelton | 20 | Jerome County | 817 |
| Carey | 21 | Blaine County | 688 |
| Richfield | 22 | Lincoln County | 493 |
| Eden | 23 | Jerome County | 407 |
| Gannett | 24 | Blaine County | 395 |
| Declo | 25 | Cassia County | 364 |
| Dietrich | 26 | Lincoln County | 314 |
| Hollister | 27 | Jerome County | 278 |
| Bliss | 28 | Gooding County | 269 |
| Albion | 29 | Cassia County | 251 |
| Castleford | 30 | Twin Falls County | 232 |
| Malta | 31 | Cassia County | 182 |
| Acequia | 32 | Blaine County | 138 |
| Murtaugh | 33 | Twin Falls County | 124 |
| Minidoka | 34 | Minidoka County | 90 |
Twin Falls County, Jerome County, Cassia County, Blaine County, Minidoka County, Gooding County and Lincoln County are the counties that are generally considered part of South Idaho.