| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Decorah | 1 | 7,369 | 7,582 | -0.65% | 1,017 | 7 | City |
| Calmar | 2 | 1,090 | 1,130 | -0.73% | 971 | 1 | City |
| Ossian | 3 | 769 | 801 | -0.77% | 720 | 1 | City |
| Spillville | 4 | 365 | 384 | -1.08% | 831 | 0 | City |
| Fort Atkinson | 5 | 298 | 308 | -1% | 937 | 0 | City |
| Ridgeway | 6 | 264 | 275 | -1.12% | 350 | 1 | City |
| Castalia | 7 | 141 | 145 | -0.7% | 244 | 1 | City |
Decorah is the largest city in Winneshiek County, with a population of 7,369.
Castalia is the smallest city in Winneshiek County, with a population of 141.
There are 7 cities in Winneshiek County, Iowa.