312 Area Code Information

Area code 312 covers 27 cities inside the state of Illinois. There are currently 11 area codes dividing up Illinois. Illinois area codes are used by over 12901563 residents across 102 different counties. Illinois became a state on December 3 1818.

The 312 is located in the Central Time Zone. There are 39 different phone service providers which use 633 different telephone exchange combinations

Counties using 312
Cook, Dupage, Lake, Will,

Cities using 312
View More Cities in 312
Other Illinois Area Codes
217 224 309 312 618 630 708 773 779 815 847

Top 10 Providers in 312
Ameritech Illinois, New Cingular, Cellco Partnership, Unknown , Broadwing Communications, Arch Wireless, Teleport Communications, Allegiance Telecom., Sprint Spectrum, Rcn Telecom,

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