O'Fallon, Illinois
Central Time Zone (UTC-6) · IL · —
About Area Codes in O'Fallon, Illinois
O'Fallon, Illinois is served by 2 area codes: 618, 730. When multiple area codes serve the same geographic area, it typically indicates overlay codes have been added to accommodate growing demand for phone numbers. All local calls within O'Fallon require 10-digit dialing. The city is in the Central time zone (UTC-6).
Other cities in area code 618
Frequently Asked Questions
What area code is O'Fallon, Illinois?
O'Fallon, Illinois uses area codes 618 and 730.
What time zone is O'Fallon in?
O'Fallon is in the Central time zone (UTC-6).
Do I need to dial 10 digits when calling O'Fallon?
Yes, all local calls in O'Fallon require 10-digit dialing because the area is served by multiple overlay area codes.
When was area code 618 created?
Area code 618 is one of the original 86 area codes established in 1947 as part of the North American Numbering Plan (NANP).
What cities share area code 618 with O'Fallon?
Other cities sharing area code 618 with O'Fallon include Alton, Belleville, Carbondale, Collinsville, East St. Louis, among others.
Also called O'Fallon:
O'Fallon, IL · Central Time Zone