ZIP code · Alton · Iowa · United States
ZIP code 51003 — Alton
ZIP code 51003 serves Alton, Iowa.
- Postal code
- 51003Single source Value from one source, not cross-checked.
- City
- Alton
- County
- Sioux
- State
- Iowa
- Country
- United States
- Coordinates
- 42.9782, -96.0173 — precision precise (locality)
View on OpenStreetMap - Population
- 1,815 (ZCTA, ACS 5-year)
- Median household income
- $85,909
- Median age
- 34.7
- Time zone
- America/Chicago (UTC−6 / UTC−5 DST)
- Area code
- 712Telephone area codes serving this ZIP (NANPA central-office assignments). A ZIP and an area code are different boundaries; at a border both codes may apply.
About this page
US ZIP codes have five digits. They are postal routing areas, not administrative boundaries: a ZIP can span more than one city or county, and the city shown is the primary USPS name for that code.
GeoNames · U.S. Census Bureau (ACS). Data generated on 2026-08-21. Methodology · Report an error on this page