Columbia County, Oregon

Columbia County, Oregon
Columbia County Courthouse in St. Helens
Location within the U.S. state of Oregon
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.