List of Illinois area codes
This is a list of the area codes in the state of Illinois and the geographic area of each numbering plan area:
- 217: Central Illinois, and part of Southern Illinois running west from the Illinois-Indiana border through Danville, Effingham, Champaign–Urbana, Decatur, Springfield, Quincy until Illinois' western border with Missouri and Iowa.
- 309: Central-Western Illinois including Bloomington–Normal, Peoria, and all the way west to the Illinois part of the Quad Cities including Moline, and Rock Island.
- 312: Chicago, the central city area including the Chicago Loop and the Near North Side.
- 630/331: West suburbs of Chicago in DuPage County and Kane County including Wheaton, Naperville, and Aurora. Area code 630 was overlaid with area code 331 in 2007.
- 618: Southern Illinois, including Carbondale and most of the Metro East region of St. Louis suburbs in Illinois
- 708: South suburbs and inner west suburbs of Chicago, including the Chicago Southland and most west and south suburbs in Cook County such as Oak Park, Oak Lawn, Chicago Heights, and Orland Park.
- 773: Chicago, covers most of the geographical area of Chicago except the downtown Chicago Loop, which is in area code 312.
- 815/779: Northern Illinois outside of the immediate Chicago area including Joliet, Kankakee, LaSalle, DeKalb, and Rockford. Area code 815 was overlaid with area code 779 in 2007.
- 847/224: North and northwest suburbs of Chicago including all of Lake County, part of McHenry County, northern Cook County, and northeastern Kane County. This area includes Evanston, Des Plaines, Waukegan, and most of Elgin. Area code 847 was overlaid with area code 224 in 2002.
- 872: City of Chicago, overlaying area codes 312 and 773.
History
In the group of original North American area codes, established in 1947, all of Chicago was part of the 312 numbering plan area, the rest of northern Illinois was 815, central Illinois was 217, and southern Illinois was 618. In 1957, area code 815 was split for the assignment of area code 309 to western central Illinois. In 1990, area code 708 was created for all of the suburbs in the Chicago metropolitan area while the city of Chicago kept the original 312. Area codes 847 (northern suburbs) and 630 (western suburbs) were created from a split of suburban area code 708 in 1996. Shortly after in 1996, area code 773 was created for the residential parts of the city of Chicago, while downtown kept area code 312. Area code 847 exhausted its numbers quickly, so that an overlay area code, 224, was implemented in 1996 for relief. However, mandatory ten-digit dialing was not in effect until 2002. In March 2007, an overlay plan was created for NPA 630 adding area code 331, and 779 was added to 815. With the depletion of new numbers in area codes 312 and 773, an overlay of both of them, area code 872, was created in November 2009, beginning ten-digit dialing within the city limits of Chicago.
Area code 464 is reserved for an overlay of 708, but has not been implemented and no timeline exists. Likewise, area code 730 reserved for an overlay of 618 in the near future, but no timeline exists. So far there are no immediate plans for relief for area code 309, but area code 447 will be implemented as an overlay for 217 beginning in 2021.
