ZIP Code 57421

ZIP code 57421 is classified by USPS as a standard delivery area and covers roughly 97.8 square miles in Amherst, Marshall County, South Dakota. The area is home to 88 residents, producing a population density of 1 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 57421 against South Dakota and the nation.

On the economic side, the median household income for ZIP 57421 sits at —, while per-capita income is $33,005. The poverty rate stands at 0.0% and the unemployment rate at 0.0%. On housing, the median home value is — with median rent at — per month, and 100.0% of occupied units are owner-occupied — a direct signal of whether 57421 behaves more like a homeowner neighborhood or a renter-heavy ZIP.

Education and household profile round out the picture: 90.9% of adults hold a bachelor's degree or higher, the median age is 16.6, and the average commute is —. We also surface 2 nearby ZIP codes within roughly 10 miles and 5 additional ZIPs sharing Marshall County, so you can benchmark 57421 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.