Washington County ZIP Codes

Washington County is a county of Kansas.

ZIP codes: 11
Cities & towns: 11
Area codes: 1
Land area: 895 sq mi

Every ZIP code in Washington County

669xx

The complete list of Washington County, KS ZIP codes with the city each one delivers to.
ZIP code	City
66933	Barnes
66937	Clifton
66943	Greenleaf
66944	Haddam
66945	Hanover
66946	Hollenberg
66953	Linn
66955	Mahaska
66958	Morrowville
66962	Palmer
66968	Washington

We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP.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 Washington County codes above are listed without a column we would have to invent.

Cities and towns in Washington County

Area codes covering Washington County

Telephone and postal boundaries are drawn by different bodies, so these codes overlap the county without matching its edges.

785 Area code 785

Where Washington County's ZIP codes sit

Each point is the reference point of one Washington County ZIP code, plotted from its record coordinates. The outline is the convex envelope of those points — a footprint, not a boundary.

Reference points and footprint
Not an official NANPA boundary
Not a USPS delivery area

Scope every ZIP code recorded in Washington 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 16 July 2026. The outline is a convex envelope of ZIP reference points, not a jurisdiction boundary.