Zip Code 63121 — Saint Louis, MO
63121 is a ZIP Code associated with Saint Louis, MO, located within St. Louis. 63121 ranks #20 out of 63 ZIP codes in St. Louis County by population (and #71 out of 1,035 in MO). The area supports an estimated population of 25,008 residents across Data Pending housing units, with a population density of 1,426.0 people per square mile.
WorldPlaceData database updated: October 2026
📍 View location on OpenStreetMap (38.707390, -90.300230)
| Data Metric | Local Statistic |
|---|
| Postal / Zip Code | 63121 |
| Primary City | Saint Louis |
| State / Province | MO |
| County | St. Louis |
| Total Population | 25,008 |
| Median Household Income | Data Pending |
| Total Housing Units | Data Pending |
| Population Density | 1,426.0 people/sq mi |
| Timezone | America/Chicago |
How 63121 Compares
| Metric | ZIP 63121 | St. Louis County | MO State Average |
|---|
| Population | 25,008 | 1,308,579 (Total) | 6,191,989 (Total) |
| Average ZIP Income | Data Pending | N/A | N/A |
| Population Density | 1,426.0 /sq mi | -- | -- |
| County Pop Rank | #20 of 63 | -- | -- |
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 →