7 cities
| City | County | 2026 Pop. ↓ |
|---|---|---|
| Urbana | Champaign County | 40,313 |
| University Park | Will County | 6,999 |
| Union | McHenry County | 760 |
| Ursa | Adams County | 578 |
| Ullin | Pulaski County | 450 |
| Unity | Alexander County | 188 |
| Union Hill | Kankakee County | 51 |