Area Code 312

Area Code 312 is in Illinois

Other Illinois Area Codes
217, 224, 309, 312, 331, 618, 630, 708, 773, 779, 815, 847, 872

Illinois Area Code Overlays
(847 and 224) - (815 and 779)
(630 and 331) - (312 and 872)
(773 and 872)

Area Code 312 History:

01/01/1947
Area code 312 was put into service. In 1989 Area code 312 was split to form area code 708. In 1996 area code 312 was split again to form area code 773. In 2009 area code 312 was overlaid with area code 872.

Counties in Illinois within area code 312 include:

Cook County.

Major cities or places in Illinois within area code 312 include:

Chicago originally utilized area code 312 which was one of the original area codes assigned to Illinois in 1947. In 1996 area code 312 was split to form area code 773. Area code 312 now serves the downtown area, or inside "The Loop" and area code 773 serves the remainder of the city. On November 7, 2009 area code 872 was put into service. Area code 872 is an overlay of of both 312 and 773.

Illinois Area Code Map

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