Midwest region · Central Time
Illinois Area Codes
All 17 area codes serving Illinois, the cities each one covers, and which are overlays. Illinois is served by 17 area codes in the Central Time zone.
Last updated October 3, 2026
Full list
Every Illinois area code
Illinois is served by 17 area codes in the Central Time zone. 8 of these are overlay codes layered over busy metros; the rest are geographic codes.
| Code | Area served | Type | In service |
|---|---|---|---|
| 217 | Central Illinois including Springfield, Champaign-Urbana, Decatur and Quincy | Geographic | Since 1947 |
| 224 | Northern and northwest Chicago suburbs in Cook, Lake and McHenry counties | Overlay | Since 2002 |
| 309 | West-central and northwest Illinois including Peoria, Bloomington-Normal and the Quad Cities | Geographic | Since 1957 |
| 312 | Downtown Chicago, including the Loop and nearby central neighborhoods | Geographic | Since 1947 |
| 331 | Western Chicago suburbs in DuPage, Kane, Kendall and northern Will counties | Overlay | Since 2007 |
| 447 | Central Illinois including Springfield, Champaign-Urbana, Decatur and Quincy | Overlay | Since 2021 |
| 464 | Western and southern Chicago suburbs in Cook and Will counties | Overlay | Since 2022 |
| 618 | Southern Illinois, including the Metro East near St. Louis and Carbondale | Geographic | Since 1947 |
| 630 | Western Chicago suburbs in DuPage, Kane, Kendall and northern Will counties | Geographic | Since 1996 |
| 708 | Western and southern Chicago suburbs in Cook and Will counties | Geographic | Since 1989 |
| 730 | Southern Illinois, including the Metro East near St. Louis and Carbondale | Overlay | Since 2023 |
| 773 | The City of Chicago outside the downtown 312 area | Geographic | Since 1996 |
| 779 | Northern Illinois outside the Chicago core, including Rockford, Joliet and Kankakee | Overlay | Since 2007 |
| 815 | Northern Illinois outside the Chicago core, including Rockford, Joliet and Kankakee | Geographic | Since 1947 |
| 847 | Northern and northwest Chicago suburbs in Cook, Lake and McHenry counties | Geographic | Since 1996 |
| 861 | West-central and northwest Illinois including Peoria, Bloomington-Normal and the Quad Cities | Overlay | Since 2023 |
| 872 | The entire city of Chicago, overlaying both 312 (downtown) and 773 (the rest of the city) | Overlay | Since 2009 |
Area codes and dialing in Illinois
Illinois's 17 area codes mix older geographic codes with newer overlays. The busiest metros — around Springfield, Chicago, Belleville — carry the most numbers and rely on overlays, which is why 10-digit dialing is required there. Quieter parts of the state may still use a single code. The oldest code in Illinois is 217 (Springfield), one of the original 1947 area codes.
Whenever a Illinois region runs low on numbers, a new overlay is added on top rather than splitting the map, so existing customers keep their numbers. See 10-digit dialing for what that means in practice, or the newest area codes for upcoming changes.
Illinois city area code pages
Look up the area codes for a specific Illinois city: Chicago · Aurora · Belleville · Cicero · Elgin · Peoria · Rockford · Springfield.
Browse Illinois another way
Explore by Midwest region, by time zone, or jump to the city index. You can also see the complete numeric list of every US area code.
Quick answers
Illinois area code FAQ
How many area codes does Illinois have?
Illinois currently has 17 area codes: 217, 224, 309, 312, 331, 447, 464, 618, 630, 708, 730, 773, 779, 815, 847, 861, 872.
What is the main area code for Illinois?
Illinois has no single main code. Its original 1947 area codes were 217, 312, 618 and 815; today the main cities are served by 217 (Springfield), 312 (Chicago), 618 (Belleville), 815 (Rockford), 309 (Peoria).
Does Illinois require 10-digit dialing?
Yes, in its overlay areas you must dial all 10 digits, even for local calls. Dialing all 10 digits always works, so it is the safe habit.