12 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mason City | 1 | 26,664 | 27,269 | -0.45% | 957 | 27.86 | City |
| Clear Lake | 2 | 7,505 | 7,660 | -0.41% | 696 | 10.78 | City |
| Rockwell | 3 | 1,027 | 1,069 | -0.77% | 345 | 2.97 | City |
| Ventura | 4 | 687 | 712 | -0.72% | 387 | 1.78 | City |
| Thornton | 5 | 385 | 404 | -1.03% | 309 | 1.24 | City |
| Plymouth | 6 | 361 | 381 | -1.1% | 819 | 0.44 | City |
| Meservey | 7 | 207 | 219 | -0.96% | 138 | 1.50 | City |
| Rock Falls | 8 | 142 | 149 | -0.7% | 686 | 0.21 | City |
| Swaledale | 9 | 136 | 143 | -0.73% | 546 | 0.25 | City |
| Dougherty | 10 | 59 | 63 | -1.67% | 105 | 0.56 | City |
| Portland | 11 | 35 | 27 | 6.06% | 35 | 0.99 | CDP |
| Burchinal | 12 | 26 | 20 | 8.33% | 338 | 0.08 | CDP |
Mason City is the largest city in Cerro Gordo County, with a population of 26,664.
Burchinal is the smallest city in Cerro Gordo County.
There are 12 cities in Cerro Gordo County, Iowa.