O'Fallon Area Codes, Missouri, Unites States

How to call O'Fallon, Missouri?

O'Fallon has 1 area code. To call O'Fallon you need to dial the Unites States country code (+1) and the following area code:

636

How to know if I'm receiving calls from O'Fallon, Missouri?

You are receiving calls from O'Fallon when the phone number starts with the following combination:

1-636

Other area codes in Unites States