Columbia County, Washington
Columbia County, Washington, has 4,141 residents (July 2025 estimate). Its county seat is Dayton. It uses Pacific Time and covers 869 sq mi (2,250 km²) of land.
- Resident population, July 2025
- 4,141
- Land area
- 869 sq mi (2,250 km²)
- County seat or government
- Dayton
- Time zone
- Pacific TimeUTC-08:00 in January; UTC-07:00 in July
- Median household income
- $71,810 ± $5,338
- Median home value
- $271,200 ± $29,295
- Median rent, with utilities
- $985 ± $65
- Homes lived in by their owners
- 77.7% ± 3.7 points
- County type
- County
- Metro or micro area
- Outside any metro or micro areaNext to: Walla Walla, WA metro area, Pullman, WA micro area, and Kennewick-Richland, WA metro area
- Water area
- 4.85 sq mi (12.6 km²)
- State
- Washington
- County code (FIPS)
- 53013
- Coordinates (central point)
- 46.292850, -117.911634
These coordinates mark a central point for the area, not a street address. Income, home value, rent and homes lived in by their owners: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, ± margin at 90% confidence; checked on October 13, 2026.
Time zones in Columbia County
| Time zone | Local time and UTC offset | Next clock change |
|---|---|---|
| Pacific TimeAmerica/Los_Angeles | UTC-08:00 in January; UTC-07:00 in July. Enable JavaScript for the live clock. | Enable JavaScript for upcoming changes. |
Near a time-zone line, check where you are with the time-zone finder. Your phone’s setting can differ.
ZIP Code areas, largest first
5 ZIP Code areas overlap Columbia County. People counts are 2020–2024 estimates for each whole ZIP area. Mailing ZIPs can differ; check an address with USPS ZIP Code Lookup.
Official county information
Columbia County government website ↗ is the next stop for county offices, tax, voting, jury and records information. A geographic lookup cannot determine eligibility, tax liability or a court obligation.
School districts in Columbia County, largest first
- Dayton School District3,749 people
- Pomeroy School District2,340 people
- Prescott School District1,636 people
- Waitsburg School District1,613 people
- Starbuck School District108 people
Districts with land in the county; a district can cross county lines. People counts are American Community Survey 2020–2024 5-year estimates. A district boundary doesn’t decide which school a student attends.
Tribal areas in Columbia County, largest first
American Indian, Alaska Native and Native Hawaiian areas as the Census Bureau maps them, with at least 2% of their area here, water included. These lines don’t decide membership, jurisdiction or land status.
Cities, towns and communities, largest first
These areas overlap the mapped boundary; an overlap does not mean that every address belongs to both.
- Dayton, Washington (city)2,774 people
- Starbuck, Washington (town)93 people
Bordering areas, nearest first
Distances are straight lines between map points.
- Garfield County, Washington20 mi northeast
- Walla Walla County, Washington27 mi west
- Whitman County, Washington46 mi northeast
- Franklin County, Washington50 mi west
- Wallowa County, Oregon60 mi southeast
Before using this answer on a form
Use a precise point for address-level questions. A device accuracy circle can cross a boundary; confirm tax, voting or jury details with the responsible office.
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