Onawa Iowa ZIP Codes

Onawa holds a single ZIP code.

Every ZIP code in Onawa

The complete list of Onawa, Iowa ZIP codes with the county each falls in.
ZIP code	County
51040	Monona County

We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP.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

Scope every ZIP code recorded for Onawa. Source GeoNames US postal codes (2026-07 postal dump) and Census 2024 county Gazetteer (2024 Gazetteer). Updated 15 July 2026. ZIP codes are delivery-route groupings, not areas; the boundaries implied by any ZIP map are approximations.

How these codes cluster

Every Onawa ZIP code begins 510. Those first three digits identify the sectional center facility that processes mail for this part of Iowa. Statewide that range covers 55 ZIP codes, so Onawa accounts for 2% of it.

Every Iowa ZIP prefix and the region it covers →

Area codes covering Onawa

ZIP codes and area codes are separate systems — one routes mail, the other routes calls — and they do not share boundaries. The code below serves the same ground Onawa occupies.

712 Area code 712

Onawa Iowa area codes in full →

Where Onawa's ZIP codes sit

Each point is one Onawa ZIP code, plotted from its record coordinates.

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

Cities near Onawa

The closest places to Onawa with their own ZIP code list, nearest first.
City	Distance	ZIP codes
Blencoe Iowa ZIP codes	6.7 mi	1 ZIP code
Whiting Iowa ZIP codes	7.6 mi	1 ZIP code
Castana Iowa ZIP codes	9.8 mi	1 ZIP code
Hornick Iowa ZIP codes	14 mi	1 ZIP code
Moorhead Iowa ZIP codes	14 mi	1 ZIP code
Rodney Iowa ZIP codes	14 mi	1 ZIP code
Little Sioux Iowa ZIP codes	15 mi	1 ZIP code
Sloan Iowa ZIP codes	16 mi	1 ZIP code

Straight-line distance between place reference points, not driving distance.