
Columbia County
- State:
- Oregon
- County Seat:
- St. Helens
Columbia County's estimated 2025 population is 54,426 with a growth rate of 0.5% in the past year according to the most recent United States census data. Columbia County is the 17th largest county in Oregon. The 2010 population was 49,353 and has seen a growth of 10.28% since that time.