Every ZIP code in O'Brien County

510xx–513xx

The complete list of O'Brien County, IA ZIP codes with the city each one delivers to.
ZIP code	City
51009	Calumet
51046	Paullina
51058	Sutherland
51201	Sheldon
51231	Archer
51245	Primghar
51248	Sanborn
51346	Hartley

We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP.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

Cities and towns in O'Brien County

Area codes covering O'Brien County

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

Where O'Brien County's ZIP codes sit

Each point is the reference point of one O'Brien 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 O'Brien 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.