| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Twin Falls | 1 | 57,077 | 52,112 | 1.53% | 2,873 | 20 | City |
| Kimberly | 2 | 6,031 | 4,648 | 4.02% | 2,967 | 2 | City |
| Buhl | 3 | 4,849 | 4,566 | 1% | 2,581 | 2 | City |
| Filer | 4 | 3,089 | 2,784 | 2.08% | 2,103 | 1 | City |
| Hansen | 5 | 1,114 | 1,092 | 0.45% | 3,192 | 0 | City |
| Castleford | 6 | 233 | 215 | 1.3% | 2,427 | 0 | City |
| Murtaugh | 7 | 125 | 116 | 0.81% | 556 | 0 | City |
Twin Falls is the largest city in Twin Falls County, with a population of 57,077.
Murtaugh is the smallest city in Twin Falls County, with a population of 125.
There are 7 cities in Twin Falls County, Idaho.