Founded in 1864, Union County is one of 36 counties in the state of Oregon. Historically, Union County was formed from Baker County. The city of La Grande is the county seat. With FIPS code of 61, Union County has a population of 26,212 and area of 2,037 square miles (5,276 km2).
List of all cities in Union County, OR alphabetically
| City/Town | Postal Code | Area Code |
| Cove, OR | 97824 | 541 |
| Elgin, OR | 97827 | 541 |
| Imbler, OR | 97841 | 541 |
| Island City, OR | 97850 | 541 |
| La Grande, OR | 97850 | 541 |
| North Powder, OR | 97867 | 541 |
| Summerville, OR | 97876 | 541 |
| Union, OR | 97883 | 541 |