Mason County ZIP Codes

Mason County is a county of Illinois.

ZIP codes: 9
Cities & towns: 9
Area codes: 4
Land area: 539 sq mi

Every ZIP code in Mason County

615xx–626xx

The complete list of Mason County, IL ZIP codes with the city each one delivers to.
ZIP code	City
61532	Forest City
61546	Manito
61567	Topeka
62617	Bath
62633	Easton
62644	Havana
62655	Kilbourne
62664	Mason City
62682	San Jose

We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP.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

Cities and towns in Mason County

Area codes covering Mason County

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

Where Mason County's ZIP codes sit

Each point is the reference point of one Mason 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 Mason 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.