Area Code 331 at a Glance
| Area code | 331 |
| Region | Illinois |
| Country | United States |
| Primary timezone | America/Chicago |
| Dialing format | +1 (331) NXX-XXXX |
Frequently Asked Questions
Where is area code 331?
Area code 331 serves Illinois, United States.
Who is calling me from area code 331?
A call from area code 331 most likely originates from Illinois, but caller ID can be spoofed. If an unknown caller asks for personal or payment information, hang up and call the organization back on its official number.
How do I dial a 331 number?
Within North America: dial 1-331 followed by the 7-digit number. From abroad: your international prefix (like 00 or +), then 1 331 and the number.