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
Arlington Heights
Ashburn Park
Berwyn
Blue Island
Bolingbrook
Burr Ridge
Calumet City
Calumet Park
Carol Stream
Chicago
Countryside
Elk Grove Village
Evanston
Glenview
Highland Park
Hoffman Estates
Homewood
Hubbard Woods
Joliet
Naperville
Niles
Northbrook
Schaumburg
Skokie
View More Cities in 312Other 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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