Columbia County, Oregon

Columbia County
Columbia County Courthouse in St. Helens
Location within the U.S. state of Oregon
Oregon's location within the U.S.
Coordinates: 45°57′N 123°05′W / 45.95°N 123.08°W / 45.95; -123.08
Country United States
State Oregon
FoundedJanuary 16, 1854
Named afterColumbia River
SeatSt. Helens
Largest citySt. Helens
Area
  Total
688 sq mi (1,780 km2)
  Land657 sq mi (1,700 km2)
  Water31 sq mi (80 km2)  4.5%
Population
 (2020)
  Total
52,589
  Estimate 
(2024)
54,063
  Density75/sq mi (29/km2)
Time zoneUTC−8 (Pacific)
  Summer (DST)UTC−7 (PDT)
Congressional district1st
Websitewww.columbiacountyor.gov

Columbia County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 52,589. The county seat is St. Helens.