Home > IA > Sioux County > Alton > Zip 51003

Zip Code 51003 — Alton, IA

51003 is a ZIP Code associated with Alton, IA, located within Sioux. The postal region supports an estimated population of 1,938 residents across Data Pending housing units, with a population density of 13.8 people per square mile.
WorldPlaceData database updated: October 2026

📍 View location on OpenStreetMap (42.983550, -95.986420)

Data MetricLocal Statistic
Postal / Zip Code51003
Primary CityAlton
State / ProvinceIA
CountySioux
Total Population1,938
Median Household IncomeData Pending
Total Housing UnitsData Pending
Population Density13.8 people/sq mi
TimezoneAmerica/Chicago

How 51003 Compares

MetricZIP 51003Sioux CountyIA State Average
Population1,93841,7023,210,984
Median IncomeData PendingN/AN/A
Population Density13.8 /sq mi----

Nearby ZIP Codes

ZIP CodeCityDistancePopulationMedian Income
Zip 51041Orange City5.4 mi7,324N/A
Zip 51022Granville7.0 mi960N/A
Zip 51238Hospers8.0 mi1,502N/A
Zip 51036Maurice10.3 mi445N/A
Zip 51045Oyens11.9 mi66N/A

Data Sources & Methodology: Geographic coordinates and ZIP Code assignments are derived from underlying geographic and postal datasets. Note that ZIP Codes are USPS postal delivery areas, while Census ZCTAs are statistical approximation areas. Read full methodology →