ZIP code 57421: Amherst, SD
57421 is a ZIP code in Amherst, South Dakota, mainly in Marshall County. About 75 people live here.
- Population
- 75
- Median household income
- —
- Typical home value
- —
- Median rent
- —gross, per month
- Median age
- 16.6
- Homeowners
- 100%of occupied homes
Shaded: ZIP code 57421's area. Click anywhere on the map to see which ZIP code it's in.
ZIP codes within 10 milesWithin 25 miles
ZIP code 57421 details
| City | Amherst |
|---|---|
| State | South Dakota |
| County | Marshall County |
| Metro area | Not in a metro or micro area |
| Time zone | Central Time (UTC−6), observes daylight saving time |
| Type | Standard (delivery area) |
| Land area | 33.3 sq mi, plus 0.1 sq mi of water |
| Population density | 2 people per sq mi |
| Bachelor's degree or higher | 90.9% of adults 25+ |
| Center coordinates | 45.75548, -97.90706 |
ZIP codes near 57421
| ZIP code | City | Distance | Population |
|---|---|---|---|
| 57432 | Claremont, SD | 7.8 mi | 507 |
| 57430 | Britton, SD | 10.6 mi | 1,828 |
| 57454 | Langford, SD | 12.2 mi | 732 |
| 57449 | Houghton, SD | 13.1 mi | 357 |
| 57446 | Hecla, SD | 14.3 mi | 223 |
| 57468 | Pierpont, SD | 19.7 mi | 279 |
| 58017 | Cogswell, ND | 20.1 mi | 296 |
| 57433 | Columbia, SD | 21.5 mi | 318 |
Population and median household income: ACS 2020–2024 5-year estimates. Typical home value: Zillow Home Value Index (September 2026) where available, otherwise the ACS median owner-reported value. "PO Box" marks ZIP codes with no delivery area of their own. Methodology
About ZIP code 57421
What city is ZIP code 57421?
ZIP code 57421 is in Amherst, SD, in Marshall County.
What county is ZIP code 57421 in?
57421 is mainly in Marshall County, South Dakota.
What is the population of ZIP code 57421?
About 75 people live in ZIP code 57421, according to the American Community Survey 2020–2024 5-year estimates.
What time zone is ZIP code 57421 in?
57421 is in Central Time (UTC−6). It observes daylight saving time.