Columbia County, Washington ZIP codes
2 ZIP codes are in Columbia County, plus 3 that cross in from neighboring counties.
- ZIP codes
- 2
- Population in these ZIPs
- 3,740
- Avg. median income
- $72,500population-weighted
- Cities & towns
- 2
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ZIP codes in Columbia County
| ZIP code | City | Population | Median income | Typical home value |
|---|---|---|---|---|
| 99328 | Dayton | 3,646 | $72,756 | $273,500 |
| 99359 | Starbuck | 94 | $61,000 | $135,400 |
ZIP codes partly in Columbia County
These ZIP codes are mostly in a neighboring county but cover part of Columbia County.
| ZIP code | City | County | Population | Median income | Typical home value |
|---|---|---|---|---|---|
| 99347 | Pomeroy | Garfield County | 2,512 | $64,699 | $242,800 |
| 99348 | Prescott | Walla Walla County | 1,633 | $79,167 | $237,200 |
| 99361 | Waitsburg | Walla Walla County | 1,992 | $91,367 | $367,600 |
Population and median household income: ACS 2020–2024 5-year estimates. Typical home value: Zillow Home Value Index (September 2026) where available, otherwise the ACS median owner-reported value. "PO Box" marks ZIP codes with no delivery area of their own. Methodology
Cities and towns in Columbia County
Nearby counties
Frequently asked questions
How many ZIP codes are in Columbia County, Washington?
2 ZIP codes are mainly in Columbia County, and 3 more ZIP codes from neighboring areas reach partly into it.
What cities are in Columbia County?
ZIP codes in Columbia County use the city names Dayton and Starbuck.