ZIP Code 51003

ZIP code 51003 is classified by USPS as a standard delivery area and covers roughly 144.1 square miles in Alton, Sioux County, Iowa. The area is home to 1,700 residents, producing a population density of 12 people per square mile, and falls within the Chicago time zone. These USPS and Census boundary values drive every downstream statistic on this page, including the benchmarks that compare 51003 against Iowa and the nation.

On the economic side, the median household income for ZIP 51003 sits at $101,250 (32% above the Iowa average), while per-capita income is $44,417. The poverty rate stands at 2.0% and the unemployment rate at 2.0%. On housing, the median home value is $232,700 (33% above the state average) with median rent at $813 per month, and 87.1% of occupied units are owner-occupied, a direct signal of whether 51003 behaves more like a homeowner neighborhood or a renter-heavy ZIP.

Education and household profile round out the picture: 29.2% of adults hold a bachelor's degree or higher, the median age is 37.1, and the average commute is —. We also surface 3 nearby ZIP codes within roughly 10 miles and 6 additional ZIPs sharing Sioux County, so you can benchmark 51003 against its immediate geography rather than a national average alone. Every figure is sourced from the U.S. Census Bureau American Community Survey 5-Year Estimates, HUD Fair Market Rents, and FHFA Home Price Index data, no estimates, no proprietary scoring. Verify with HUD →