Columbia County ZIP Codes
Columbia County is a county of Washington.
- ZIP codes
- 2
- Cities & towns
- 2
- Area codes
- 1
- Land area
- 869 sq mi
Every ZIP code in Columbia County
| ZIP code | City |
|---|---|
| 99328 | Dayton |
| 99359 | Starbuck |
We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP. USPS delivery-type products are licensed, and no clean-rights source maps ZIP codes to neighbourhoods — so the Columbia County codes above are listed without a column we would have to invent.
Cities and towns in Columbia County
Area codes covering Columbia County
Telephone and postal boundaries are drawn by different bodies, so these codes overlap the county without matching its edges.
Scope every ZIP code recorded in Columbia County. Source GeoNames US postal codes (2026-07 postal dump), Census 2024 county Gazetteer (2024 Gazetteer) and geoinfo-dataset (full_dataset) ZIP→NPA (2018 snapshot). Updated . The outline is a convex envelope of ZIP reference points, not a jurisdiction boundary.