| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Williamsburg | 1 | 3,416 | 3,355 | 0.23% | 1,014 | 3 | City |
| Marengo | 2 | 2,421 | 2,437 | -0.16% | 1,145 | 2 | City |
| North English | 3 | 1,035 | 1,066 | -0.58% | 1,705 | 1 | City |
| Victor | 4 | 850 | 874 | -0.58% | 1,767 | 0 | City |
| Ladora | 5 | 222 | 229 | -0.45% | 753 | 0 | City |
| Parnell | 6 | 190 | 194 | -0.52% | 1,073 | 0 | City |
| Millersburg | 7 | 137 | 137 | 0% | 1,123 | 0 | City |
Williamsburg is the largest city in Iowa County, with a population of 3,416.
Millersburg is the smallest city in Iowa County, with a population of 137.
There are 7 cities in Iowa County, Iowa.