| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Forest City | 1 | 4,122 | 4,269 | -0.51% | 898 | 5 | City |
| Lake Mills | 2 | 2,032 | 2,142 | -0.88% | 749 | 3 | City |
| Buffalo Center | 3 | 823 | 858 | -0.72% | 768 | 1 | City |
| Thompson | 4 | 466 | 494 | -1.06% | 544 | 1 | City |
| Leland | 5 | 233 | 246 | -1.27% | 174 | 1 | City |
| Rake | 6 | 175 | 186 | -1.13% | 231 | 1 | City |
| Scarville | 7 | 72 | 78 | -1.37% | 295 | 0 | City |
Forest City is the largest city in Winnebago County, with a population of 4,122.
Scarville is the smallest city in Winnebago County, with a population of 72.
There are 7 cities in Winnebago County, Iowa.