Illinois Area Code Information
Illinois Area Codes
(217 and 447) - (224 and 847)
(309 and 861) - (312 and 872)
(331 and 630) - (464 and 708)
(618 and 730) - (773 and 872)
(779 and 815)
Illinois is currently using seventeen area codes. Illinois currently utilizes nine area code overlay plans, often called an overlay complex.
Illinois originally had four area codes, 217,312,618 and 815, when the numbering system was established in 1947. It was not until ten years later in 1957 that Illinois experienced sufficient growth in population and telephone use to need an additional area code. In 1957 area code 309 was created by a split of area codes 217 and 815. These five area codes were sufficient until 1989.
Changes and History of Illinois Area Codes:
01/01/1947
Area code 217 was put into service. In 1957 area code 217 was split, along with a portion of area code 815, to form part of area code 309.
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.
01/01/1947
Area code 618 was put into service.
01/01/1947
Area code 815 was put into service. In 1957 area code 815 was split, along with a portion of area code 217, to form area code 309. In 2007 area code 815 was overlaid with area code 779.
01/01/1957
Area code 309 was put into service. Area code 309 was created from splits of area codes 217 and 815.
11/11/1989
Area code 708 was put into service. Then in 1996 portions of area code 708 were split to form area codes 847 and 630. Area code 464, which is not yet in service, has been proposed as an overlay of area code 708.
01/20/1996
Area code 847 was put into service. Area code 847 created from a split of area code 708. In 1998 area code 847 was overlaid with area code 224 but it was not put into service until 2002.
08/03/1996
Area code 630 was put into service. Area code 630 was created from a split of area code 708. In 2007 area code 630 was overlaid with area code 331.
10/12/1996
Area code 773 was put into service. Area code 773 was created from a split of area code 312. In 2009 area code 773 was overlaid with area code 872.
01/05/2002
Area code 224 was put into service. Area code 224 is an overlay of area code 847.
03/17/2007
Area code 779 was put into service. Area code 779 is an overlay of area code 815.
10/07/2007
Area code 331 was put into service. Area code 331 is an overlay of area code 630.
11/07/2009
Area code 872 was put into service. Area code 872 is an overlay of area codes 312 and 773.
03/27/2021
Area code 447 was put into service. Area code 447 is an overlay of area code 217.
01/21/2022
Area code 464 was put into service as an overlay of area code 708.
02/24/2023
Area code 861 was put into service as an overlay of area code 309.
07/07/2023
Area code 730 was put into service as an overlay of area code 618.
