Zip Code 57751 — Keystone, SD
57751 is a ZIP Code associated with Keystone, SD, located within Pennington. The postal region supports an estimated population of 893 residents across Data Pending housing units, with a population density of 7.8 people per square mile.
WorldPlaceData database updated: October 2026
📍 View location on OpenStreetMap (43.867670, -103.423460)
| Data Metric | Local Statistic |
|---|
| Postal / Zip Code | 57751 |
| Primary City | Keystone |
| State / Province | SD |
| County | Pennington |
| Total Population | 893 |
| Median Household Income | Data Pending |
| Total Housing Units | Data Pending |
| Population Density | 7.8 people/sq mi |
| Timezone | America/Denver |
How 57751 Compares
| Metric | ZIP 57751 | Pennington County | SD State Average |
|---|
| Population | 893 | 103,728 | 906,188 |
| Median Income | Data Pending | N/A | N/A |
| Population Density | 7.8 /sq mi | -- | -- |
Nearby ZIP Codes
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 →