14 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Twin Falls | 1 | 56,457 | 51,843 | 1.56% | 2,881 | 20 | City |
| Twin Falls | 2 | 56,457 | 52,116 | 1.56% | 2,881 | 20 | City |
| Kimberly | 3 | 5,826 | 4,630 | 4.18% | 2,866 | 2 | City |
| Kimberly | 4 | 5,826 | 4,653 | 4.18% | 2,866 | 2 | City |
| Buhl | 5 | 4,808 | 4,567 | 0.99% | 2,559 | 2 | City |
| Buhl | 6 | 4,808 | 4,570 | 0.99% | 2,559 | 2 | City |
| Filer | 7 | 3,103 | 2,786 | 2.07% | 2,112 | 1 | City |
| Filer | 8 | 3,103 | 2,787 | 2.07% | 2,112 | 1 | City |
| Hansen | 9 | 1,124 | 1,090 | 0.54% | 3,221 | 0 | City |
| Hansen | 10 | 1,124 | 1,091 | 0.54% | 3,221 | 0 | City |
| Castleford | 11 | 229 | 214 | 1.33% | 2,385 | 0 | City |
| Castleford | 12 | 229 | 214 | 1.33% | 2,385 | 0 | City |
| Murtaugh | 13 | 125 | 115 | 1.63% | 556 | 0 | City |
| Murtaugh | 14 | 125 | 115 | 1.63% | 556 | 0 | City |
Twin Falls is the largest city in Twin Falls County, with a population of 56,457.
Murtaugh is the smallest city in Twin Falls County, with a population of 125.
There are 14 cities in Twin Falls County, Idaho.