Columbia County Sheriff’s Office
341 East Main Street
Dayton, WA 99328
Phone: 509.382.1100
Columbia County is named after the Columbia River. It is part of the Palouse, a wide and rolling prairie-like region of the middle Columbia basin. The county seat is at Dayton, which is also the county’s largest city. As of 2017, the estimated population was 4,047.
Columbia County was created out of Walla Walla County on November 11, 1875.
According to the U.S. Census Bureau, the county has a total area of 874 square miles, of which, 869 square miles of it is land and 5 square miles of it (0.54%) is water. The population density is 5 per square mile.
Principal Communities:
- Dayton (County Seat)
- Starbuck
