9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Grinnell | 1 | 9,429 | 9,538 | -0.23% | 1,657 | 5.69 | City |
| Brooklyn | 2 | 1,442 | 1,496 | -0.76% | 1,097 | 1.31 | City |
| Montezuma | 3 | 1,424 | 1,444 | -0.28% | 577 | 2.47 | City |
| Holiday Lake | 4 | 355 | 330 | -1.66% | 133 | 2.67 | CDP |
| Malcom | 5 | 257 | 267 | -0.77% | 311 | 0.83 | City |
| Deep River | 6 | 247 | 251 | -0.4% | 565 | 0.44 | City |
| Searsboro | 7 | 125 | 129 | -0.79% | 277 | 0.45 | City |
| Hartwick | 8 | 88 | 92 | -1.12% | 557 | 0.16 | City |
| Guernsey | 9 | 59 | 63 | -1.67% | 105 | 0.56 | City |
Grinnell is the largest city in Poweshiek County, with a population of 9,429.
Guernsey is the smallest city in Poweshiek County.
There are 9 cities in Poweshiek County, Iowa.