9 cities
| City | County | 2025 Pop. ↓ |
|---|---|---|
| Urbandale | Polk County | 47,495 |
| Urbana | Benton County | 1,669 |
| University Heights | Johnson County | 1,163 |
| Underwood | Pottawattamie County | 961 |
| University Park | Mahaska County | 467 |
| Union | Hardin County | 373 |
| Ute | Monona County | 322 |
| Unionville | Appanoose County | 73 |
| Udell | Appanoose County | 29 |