Area code 312 encompasses the Chicago Loop and surrounding areas in Chicago, Illinois. It is roughly bounded by North Avenue on the north, Western Avenue on the west, and 35th Street on the south. Up until 1989, it encompassed most of Chicagoland, at that time the suburbs became area code 708 . In 1996, most of the city split off into 773 after the northern suburbs and western suburbs split into area codes 847 and 630 respectively.

Related topics

• List of North American area codes