22 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mason City | 1 | 26,865 | 27,351 | -0.31% | 964 | 28 | City |
| Mason City | 2 | 26,865 | 27,280 | -0.31% | 964 | 28 | City |
| Clear Lake | 3 | 7,586 | 7,682 | -0.21% | 704 | 11 | City |
| Clear Lake | 4 | 7,586 | 7,666 | -0.21% | 704 | 11 | City |
| Rockwell | 5 | 1,037 | 1,072 | -0.67% | 349 | 3 | City |
| Rockwell | 6 | 1,037 | 1,069 | -0.67% | 349 | 3 | City |
| Ventura | 7 | 698 | 713 | -0.43% | 393 | 2 | City |
| Ventura | 8 | 698 | 711 | -0.43% | 393 | 2 | City |
| Thornton | 9 | 391 | 405 | -0.76% | 314 | 1 | City |
| Thornton | 10 | 391 | 404 | -0.76% | 314 | 1 | City |
| Plymouth | 11 | 365 | 380 | -0.82% | 828 | 0 | City |
| Plymouth | 12 | 365 | 379 | -0.82% | 828 | 0 | City |
| Meservey | 13 | 210 | 220 | -0.94% | 140 | 1 | City |
| Meservey | 14 | 210 | 219 | -0.94% | 140 | 1 | City |
| Rock Falls | 15 | 141 | 149 | -1.4% | 681 | 0 | City |
| Rock Falls | 16 | 141 | 149 | -1.4% | 681 | 0 | City |
| Swaledale | 17 | 134 | 142 | -1.47% | 538 | 0 | City |
| Swaledale | 18 | 134 | 142 | -1.47% | 538 | 0 | City |
| Dougherty | 19 | 60 | 63 | -1.64% | 107 | 1 | City |
| Dougherty | 20 | 60 | 63 | -1.64% | 107 | 1 | City |
| Portland | 21 | 35 | 27 | 6.06% | 35 | 1 | CDP |
| Burchinal | 22 | 26 | 20 | 8.33% | 338 | 0 | CDP |
Mason City is the largest city in Cerro Gordo County, with a population of 26,865.
Burchinal is the smallest city in Cerro Gordo County, with a population of 26.
There are 22 cities in Cerro Gordo County, Iowa.