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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 2006 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.
Places in Illinois within area code 312 include:
Chicago, Fort Dearborn, Lakeview, and Pilsen. |
