Founded in 1854, Columbia County is one of 36 counties in the state of Oregon. Historically, Columbia County was formed from Northern half of Washington County. The city of Saint Helens is the county seat. With FIPS code of 9, Columbia County has a population of 53,074 and area of 657 square miles (1,702 km2).
List of all cities in Columbia County, OR alphabetically
| City/Town | Postal Code | Area Code |
| Birkenfeld, OR | 97016 | 503/971 |
| Clatskanie, OR | 97016 | 503/971 |
| Columbia City, OR | 97018 | 503/971 |
| Deer Island, OR | 97054 | 503/971 |
| Mist, OR | 97016 | 503/971 |
| Rainier, OR | 97048 | 503/971 |
| Saint Helens, OR | 97051 | 503/971 |
| Scappoose, OR | 97056 | 503/971 |
| Vernonia, OR | 97064 | 503/971 |
| Warren, OR | 97053 | 503/971 |
| Westport, OR | 97016 | 503/971 |