| Post Office | Authorized to issue & pay money orders | Discontinued for the winter | County Seat | No. of rural routes emanating therefrom | Can issue international money orders | County |
| Underhill | X | -- | -- | 2 | -- | Oconto |
| Union Center | X | -- | -- | 2 | -- | Juneau |
| Union Grove | X | -- | -- | 3 | -- | Racine |
| Unity | X | -- | -- | 1 | -- | Marathon |
| Upson | X | -- | -- | -- | -- | Iron |
| Urquhart | -- | -- | -- | -- | -- | Taylor |