O'Fallon, MO ZIP Codes
O'Fallon, Missouri has 2 ZIP codes: 2 for street addresses ( and ).
Your street decides which one you use.
Which O'Fallon ZIP code is my address in?
Street ranges from the Census Bureau, 2026. PO box and organization ZIP codes are not found by street. A new street may be missing: address not found?
O'Fallon ZIP code map
Tap or point to an area to see its ZIP code.Full-size map
Dashed line: O'Fallon city limits.
Map: Census Bureau ZIP Code Tabulation Areas (2020) and place limits (2024).
All O'Fallon ZIP codes by type
| ZIP | Type and post office or station |
|---|---|
| 63366 | street delivery O Fallon |
| 63368 | street delivery O Fallon |
ZIP codes from nearby towns that reach into O'Fallon
- 63376, mailing town Saint Peters, covers 7 percent of O'Fallon
- 63367, mailing town Lake Saint Louis, covers 5 percent of O'Fallon
- 63304, mailing town Saint Charles, covers 2 percent of O'Fallon
Why your mail may say O'Fallon when you live outside it
O'Fallon ZIP codes also cover St. Paul and Dardenne Prairie, so a letter addressed to O'Fallon can go to a home outside the city limits.
The reverse happens too: parts of O'Fallon use 63376, 63367 and 63304, which mail under a neighboring town's name.
A ZIP code does not set your city, school district or tax. St. Charles County property records show which city you are in.
O'Fallon ZIP code questions
What is the main ZIP code for O'Fallon?
63366, the ZIP code of the main O Fallon post office at 401 Church St.
What county is O'Fallon in?
St. Charles County.
ZIP codes for towns near O'Fallon
More towns near O'Fallon: Florissant, University City, St. Louis, Oakville, Belleville, O'Fallon, Jefferson City, Columbia, Quincy.
Sources and last checked
USPS ZIP Locale Detail (October 1, 2026), GeoNames (CC BY 4.0), U.S. Census Bureau, HUD-USPS crosswalk.
Checked October 20, 2026. Sources · How we build our lists · Corrections