Zip Code 63366 — O'Fallon, MO
63366 is a ZIP Code associated with O'Fallon, MO, located within St. Charles. The postal region supports an estimated population of 54,769 residents across Data Pending housing units, with a population density of 305.2 people per square mile.
WorldPlaceData database updated: October 2026
📍 View location on OpenStreetMap (38.859180, -90.719640)
| Data Metric | Local Statistic |
|---|
| Postal / Zip Code | 63366 |
| Primary City | O'Fallon |
| State / Province | MO |
| County | St. Charles |
| Total Population | 54,769 |
| Median Household Income | Data Pending |
| Total Housing Units | Data Pending |
| Population Density | 305.2 people/sq mi |
| Timezone | America/Chicago |
How 63366 Compares
| Metric | ZIP 63366 | St. Charles County | MO State Average |
|---|
| Population | 54,769 | 416,486 | 6,191,989 |
| Median Income | Data Pending | N/A | N/A |
| Population Density | 305.2 /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 →