Alton Iowa ZIP Codes

Alton holds a single ZIP code.

Every ZIP code in Alton

The complete list of Alton, Iowa ZIP codes with the county each falls in.
ZIP code	County
51003	Sioux 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We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP.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 Alton codes above are listed without a column we would have to invent.

Scope every ZIP code recorded for Alton. 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 Alton 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 Alton accounts for 2% of it.

Every Iowa ZIP prefix and the region it covers →

Area codes covering Alton

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 Alton occupies.

712 Area code 712

Alton Iowa area codes in full →

Where Alton's ZIP codes sit

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

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

Cities near Alton

The closest places to Alton with their own ZIP code list, nearest first.
City	Distance	ZIP codes
Orange City Iowa ZIP codes	2.5 mi	1 ZIP code
Granville Iowa ZIP codes	6.8 mi	1 ZIP code
Hospers Iowa ZIP codes	7.9 mi	1 ZIP code
Maurice Iowa ZIP codes	8.8 mi	1 ZIP code
Sioux Center Iowa ZIP codes	10 mi	1 ZIP code
Oyens Iowa ZIP codes	12 mi	1 ZIP code
Remsen Iowa ZIP codes	12 mi	1 ZIP code
Boyden Iowa ZIP codes	14 mi	1 ZIP code

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