Post Offices List in Union County, Oregon:
| Cove Post Office | 601 Main St, Cove, OR 97824 |
| Elgin Post Office | 887 Division St, Elgin, OR 97827 |
| Imbler Post Office | 510 Ruckman Ave, Imbler, OR 97841 |
| La Grande Post Office | 1202 Washington Ave, La Grande, OR 97850 |
| North Powder Post Office | 205 E St, North Powder, OR 97867 |
| Union Post Office | 268 S Main St, Union, OR 97883 |
| Summerville Post Office | 301 Main St, Summerville, OR 97876 |