Carter County ZIP Codes

Carter County is a county of Montana.

ZIP codes: 5
Cities & towns: 5
Area codes: 1
Land area: 3,340 sq mi

Every ZIP code in Carter County

593xx

The complete list of Carter County, MT ZIP codes with the city each one delivers to.
ZIP code	City
59311	Alzada
59316	Boyes
59319	Capitol
59324	Ekalaka
59332	Hammond

We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP.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

Cities and towns in Carter County

A further 4 places in Carter County appear in the postal source without a page of its own; their codes are in the table above and each one links to its own page.

Area codes covering Carter County

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

406 Area code 406

Where Carter County's ZIP codes sit

Each point is the reference point of one Carter 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 Carter 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.