ZIP CodesZIP codes in Columbia County, Washington
Columbia County, Washington has 2 ZIP codes in this list, from 99328 to 99359. They cover 2 places, among them Dayton and Starbuck.
| ZIP code | Place | Land area (sq mi) | Map point |
|---|---|---|---|
| 99328 | Dayton | 657 | 46.307, -117.974 |
| 99359 | Starbuck | 42.4 | 46.513, -118.102 |
The ZIP code areas of Columbia County add up to about 700 square miles of land (1,812 sq km) as the Census Bureau draws them. The largest is 99328 (Dayton), with 657 square miles.
Using these codes
- In an address, the ZIP code comes last, after the city and the two-letter state: Dayton, WA 99328.
- Tap a ZIP code to open it in the look-up, with a copy button for the address line.
- A code can cross a county line, and one town can have several codes. The table shows the main place of each code.
- "No area" means the Census Bureau draws no area for that code. Such codes are usually for post office boxes or a single building.
Places and counties: GeoNames. Areas: U.S. Census Bureau, 2024 ZIP Code Tabulation Areas. Checked in November 2026. This site is not connected with the United States Postal Service; for mailing, confirm the address with USPS.