What city is ZIP code 57421?

ZIP code 57421 is in Sunset Colony, SD (Marshall County).

What county is ZIP code 57421 in?

ZIP code 57421 is mostly in Marshall County, South Dakota.

How many people live in ZIP code 57421?

About 75 people live in the 57421 ZIP Code Tabulation Area, based on American Community Survey 5-year estimates.

Checked Oct 26, 2026

ZIP Code 57421

Sunset Colony, SD, Marshall County

Population

Land area

33.3sq mi

People per sq mi

City

Sunset Colony

ZIP 57421 and nearby ZIP codes

Full map

ZIP 57421 at a glance

ZIP 57421 (Sunset Colony) is 81% less dense than South Dakota as a whole.

Economy and federal money

Businesses, pandemic loans and political donations

Details

PPP loans

$438K

21 loans

Campaign donations

$350

100% D, 0% R, 2026 cycle

PPP loans in this ZIP

Environment and hazard risk

ZIP 57421, from FEMA, NOAA and EPA

Full report

Natural hazard risk

Very Low

Top: winter weather

Storm events since 1996

576

Countywide, mostly hail

July high / Jan low

83° / 0°F

24.3 inches of rain a year

Hazards, floods and storm history Check a flood zone

Frequently asked questions

What city is ZIP code 57421?: ZIP code 57421 is in Sunset Colony, SD (Marshall County).
What county is ZIP code 57421 in?: ZIP code 57421 is mostly in Marshall County, South Dakota.
How many people live in ZIP code 57421?: About 75 people live in the 57421 ZIP Code Tabulation Area, based on American Community Survey 5-year estimates.

Source: U.S. Census Bureau (ZIP Code Tabulation Areas, American Community Survey) · Data as of 12/31/2023. ZIP Code Tabulation Areas closely match, but are not identical to, USPS ZIP code delivery areas.