Area Code 312 at a Glance
| Area code | 312 |
| Region | Chicago, IL |
| Country | United States |
| Primary timezone | America/Chicago |
| Dialing format | +1 (312) NXX-XXXX |
About Area Code 312
312 is one of the original area codes of 1947 and once covered the whole Chicago area. Splits gave the suburbs 708 in 1989 and the rest of the city 773 in 1996, leaving 312 for downtown Chicago: the Loop, River North, the Near North Side and the surrounding central neighborhoods.
Since 2009 the overlay code 872 has served the same area as 312 and 773, which is why calls in Chicago need all ten digits. Chicago is on Central Time.
Frequently Asked Questions
Where is area code 312?
Area code 312 serves Chicago, IL, United States.
Who is calling me from area code 312?
A call from area code 312 most likely originates from Chicago, IL, 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 312 number?
Within North America: dial 1-312 followed by the 7-digit number. From abroad: your international prefix (like 00 or +), then 1 312 and the number.