Area Code 730 – Illinois
The phone area code for Illinois is 730 (international format +1730). Browse local exchange codes (NXX) and carrier assignments below.
📞 Exchange Codes (NXX) for Area Code 730
Select a central office code to view local carrier data and detailed information
📍 Geographic Location of Illinois
Geographic Coverage and Jurisdiction
Area code 730 is a geographic North American Numbering Plan (NANP) code assigned to the state of Illinois, United States. It serves the southwestern portion of the state, including the Illinois Side of the St. Louis Metropolitan Area and the Metro East region. Key cities and communities within this area code include Belleville, East St. Louis, O'Fallon, Edwardsville, Alton, Granite City, Collinsville, and Carbondale. The code covers parts of St. Clair, Madison, Monroe, and Jackson counties, among others.
Dialing Formats and Procedures
For local calls within the 730 area code, callers must use the 10-digit dialing format: 730-XXX-XXXX. This is mandatory even for calls between neighboring exchanges within the same area code. For calls originating from outside the 730 area code but within the United States or Canada, the international format is 1-730-XXX-XXXX, where '1' is the country code for the NANP. For international callers, the full international format is +1 730 XXX XXXX.
Overlay and Implementation Context
Area code 730 is an overlay code for the existing 618 area code, which was introduced to meet the growing demand for telephone numbers in the region. As an overlay, 730 does not require changes to existing 618 numbers, but it does mandate 10-digit dialing for all local calls within the overlay area. This means that even calls between two numbers with the same area code (either 618 or 730) must include the full 10-digit number.
Caller Instructions
- Local callers within the overlay area: Always dial 10 digits (area code + 7-digit number).
- Callers from other U.S. states or Canada: Dial 1-730-XXX-XXXX.
- International callers: Dial +1-730-XXX-XXXX.
For example, to call a business in Belleville from outside the area, you would dial +1 730 555 0199. If you are within the region, simply dial 730 555 0199.
Service and Regulatory Notes
Area code 730 is a geographic code, meaning it is tied to a specific physical region. However, with the rise of VoIP and number portability, a number with this area code may be used by a customer located anywhere in the country. This is important for businesses that wish to maintain a local presence in the Metro East area. The Illinois Commerce Commission (ICC) oversees the allocation and management of area codes in the state, ensuring an adequate supply of numbers for future growth.