O Fallon, MO Area Codes
O Fallon is served by area code 636. It is in Missouri, St. Charles County. About 101,735 people live in its 2 ZIP codes.
| Field | Value |
|---|---|
| Area code(s) | 636 |
| State / province | Missouri |
| County | St. Charles County |
| Population | 101,735 |
| ZIP codes | 2 |
| Time zone | Central |
| Coordinates | 38.8045, -90.7269 |
What area code is O Fallon in?
| Area code | Main state | Population covered | Overlap |
|---|---|---|---|
| 636 | Missouri | 1,007,929 | — |
ZIP codes in the code footprint
Nearby towns and their area codes
Lake Saint Louis 636Saint Peters 636Wentzville 636Saint Charles 636Foristell 636Chesterfield 636Moscow Mills 636Wright City 636
How to dial
Dial 636 + 7 digits for a number in O Fallon, or +1 636 ... from abroad. Ten-digit dialling is required everywhere in the North American Numbering Plan.