Postal reference / United States
63366O Fallon, Missouri
ZIP code 63366 is a United States postal code for O Fallon, Missouri. Its county association is Saint Charles County. The map reference point is at 38.8239, -90.7427.
- State / territory
- Missouri
- Recorded place name
- O Fallon
- County association
- Saint Charles
- Estimated coordinate
- 38.8239, -90.7427
View on OpenStreetMap - ZIP prefix
- 633 · 51 ZIP codes share it
- Data source
- GeoNames postal reference, snapshot September 26, 2026
GeoNames reference data. County associations may not include every intersecting county, place names are postal names rather than legal boundaries, and coordinates are approximate. This is not address validation.
Area
- Land area
- 69.284 sq mi (2023 Census Gazetteer)
Figures are for the ZIP Code Tabulation Area (ZCTA) that most closely matches this ZIP code, not an exact match to USPS delivery boundaries. Source: U.S. Census Bureau, 2023 Gazetteer + 2023 ACS 5-Year Estimates, retrieved 2026-09-27. How to read this data.
Need the last four digits?
ZIP+4 depends on the full delivery address. A five-digit code alone cannot determine its extension.
Find ZIP+4Explore Missouri
Browse the other 1,156 ZIP codes recorded for Missouri, sorted by code with place and county.
Missouri directoryOther ZIP codes in O Fallon, MO
O Fallon has 2 ZIP codes in the reference dataset.
- 63368Saint Charles
Nearby ZIP code reference points
| ZIP code | Place | State | County association | Miles |
|---|---|---|---|---|
| 63367 | Lake Saint Louis | MO | Saint Charles | 3.1 |
| 63368 | O Fallon | MO | Saint Charles | 5.1 |
| 63385 | Wentzville | MO | Saint Charles | 6.1 |
| 63376 | Saint Peters | MO | Saint Charles | 7.1 |
| 63338 | Cottleville | MO | Saint Charles | 7.2 |
| 63369 | Old Monroe | MO | Lincoln | 7.9 |
| 63304 | Saint Charles | MO | Saint Charles | 8.8 |
| 63365 | New Melle | MO | Saint Charles | 10.3 |
Straight-line distance between reference points. Nearby points do not prove that ZIP areas touch.
Verify a mailing address
For mailing, confirm the complete street or PO Box address with USPS. A place record does not confirm delivery eligibility or the ZIP+4 extension.
Open USPS address lookup