9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Grinnell | 1 | 9,484 | 9,537 | -0.12% | 1,667 | 6 | City |
| Brooklyn | 2 | 1,467 | 1,499 | -0.47% | 1,116 | 1 | City |
| Montezuma | 3 | 1,415 | 1,445 | -0.42% | 573 | 2 | City |
| Holiday Lake | 4 | 355 | 330 | -1.66% | 133 | 3 | CDP |
| Malcom | 5 | 254 | 267 | -1.17% | 308 | 1 | City |
| Deep River | 6 | 242 | 247 | -0.41% | 554 | 0 | City |
| Searsboro | 7 | 128 | 130 | -0.78% | 284 | 0 | City |
| Hartwick | 8 | 90 | 92 | -1.1% | 570 | 0 | City |
| Guernsey | 9 | 58 | 61 | -1.69% | 103 | 1 | City |
Grinnell is the largest city in Poweshiek County, with a population of 9,484.
Guernsey is the smallest city in Poweshiek County, with a population of 58.
There are 9 cities in Poweshiek County, Iowa.