11 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Garner | 1 | 3,047 | 3,055 | -0.07% | 1,434 | 2 | City |
| Britt | 2 | 1,992 | 2,037 | -0.45% | 1,487 | 1 | City |
| Kanawha | 3 | 634 | 652 | -0.63% | 320 | 2 | City |
| Klemme | 4 | 426 | 439 | -0.7% | 852 | 1 | City |
| Corwith | 5 | 257 | 265 | -0.77% | 177 | 1 | City |
| Crystal Lake | 6 | 240 | 253 | -1.23% | 968 | 0 | City |
| Woden | 7 | 182 | 187 | -0.55% | 369 | 0 | City |
| Goodell | 8 | 138 | 142 | -0.72% | 319 | 0 | City |
| Duncan | 9 | 67 | 102 | -6.94% | 85 | 1 | CDP |
| Miller | 10 | 65 | 30 | 6.56% | 31 | 2 | CDP |
| Hayfield | 11 | 25 | 56 | 8.7% | 26 | 1 | CDP |
Garner is the largest city in Hancock County, with a population of 3,047.
Hayfield is the smallest city in Hancock County, with a population of 25.
There are 11 cities in Hancock County, Iowa.