| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Rockwell City | 1 | 2,114 | 2,250 | -0.89% | 502 | 4 | City |
| Lake City | 2 | 1,622 | 1,722 | -1.1% | 336 | 5 | City |
| Manson | 3 | 1,600 | 1,701 | -1.05% | 494 | 3 | City |
| Pomeroy | 4 | 496 | 525 | -1% | 242 | 2 | City |
| Lohrville | 5 | 356 | 378 | -1.11% | 158 | 2 | City |
| Farnhamville | 6 | 354 | 379 | -1.12% | 537 | 1 | City |
| Lytton | 7 | 267 | 281 | -1.11% | 1,161 | 0 | City |
| Somers | 8 | 118 | 126 | -0.84% | 346 | 0 | City |
| Knierim | 9 | 50 | 54 | -1.96% | 50 | 1 | City |
| Rinard | 10 | 34 | 37 | -2.86% | 34 | 1 | City |
| Jolley | 11 | 28 | 28 | 0% | 322 | 0 | City |
| Yetter | 12 | 19 | 21 | -5% | 148 | 0 | City |
Rockwell City is the largest city in Calhoun County, with a population of 2,114.
Yetter is the smallest city in Calhoun County, with a population of 19.
There are 12 cities in Calhoun County, Iowa.