8 cities
| City | County | 2025 Pop. ↓ |
|---|---|---|
| Union charter | Isabella County | 12,043 |
| Utica | Macomb County | 5,116 |
| Unadilla | Livingston County | 3,260 |
| Union | Cass County | 3,019 |
| Union City | Branch County | 1,733 |
| Ubly | Huron County | 826 |
| Unionville | Tuscola County | 482 |
| Union | Cass County | 479 |