City · Iowa · United States
Alton, IA — ZIP codes
1 ZIP code · Sioux County
- City
- Alton
- County
- Sioux
- State
- Iowa
- Country
- United States
- Postal code
- 51003Single source
- Coordinates
- 42.9782, -96.0173 View on OpenStreetMap
ZIP codes (1)
| Postal code | Place name | Verification |
|---|---|---|
| 51003 | Alton | Single source |
Sources and verification
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). Last generated : 2026-08-21. Report an error.