Quick answer
Illinois has 15 active geographic area codes covering Chicago, Evanston, Aurora. The most-recognized codes are 217, 618, 312, serving Chicago and the Chicago region.
- Total codes
- 15
- Top metro
- Chicago
- Time zone
- CT
- Largest code
- 872 (Chicago)
- NXX prefixes in use
- 8,835
- Most saturated
- 847 (~99%)
Area codes in Illinois
Illinois is served by 15 active geographic area codes in the North American Numbering Plan. These codes were assigned between 1947 and 2021 as population and call demand grew across the state.
Across Illinois's 15 area codes, our data counts 8,835 assigned central-office (NXX) prefixes in service. The most heavily loaded is 847 (Evanston), with about 99% of its ~792 usable prefixes assigned, and 9 of the state's codes sit at 90%+ capacity — which is why overlay codes keep being added. See the full NXX prefix allocation analysis across US area codes. (Prefix data: localcallingguide.com / NANPA, 2026.)
| Code | Primary City | Region | Established | Overlay Codes | Population |
|---|---|---|---|---|---|
| 217 | Springfield | Central Illinois | 1947 | 447 | 800,000 |
| 224 | Evanston | Northern Chicago Suburbs | 2008 | 847 | 1,500,000 |
| 309 | Peoria | West-Central Illinois | 1957 | — | 700,000 |
| 312 | Chicago | Downtown Chicago | 1947 | 773, 872 | 500,000 |
| 331 | Aurora | Western Chicago Suburbs | 2007 | 630 | 1,200,000 |
| 447 | Springfield | Central Illinois | 2021 | 217 | 800,000 |
| 618 | East St. Louis | Southern Illinois | 1947 | — | 600,000 |
| 630 | Aurora | Western Chicago Suburbs | 1996 | 331 | 1,200,000 |
| 708 | Cicero | Southern Chicago Suburbs | 1989 | — | 1,200,000 |
| 730 | Chicago | Southern Chicago Suburbs | 2021 | 708 | 1,200,000 |
| 773 | Chicago | Chicago (non-Loop) | 1996 | 312, 872 | 2,700,000 |
| 779 | Rockford | Northern Illinois | 2007 | 815 | 700,000 |
| 815 | Rockford | Northern Illinois | 1957 | 779 | 700,000 |
| 847 | Evanston | Northern Chicago Suburbs | 1996 | 224 | 1,500,000 |
| 872 | Chicago | Chicago | 2009 | 312, 773 | 3,000,000 |
Time zones in Illinois
All area codes in Illinois fall in the CT time zone.
- CT — area codes: 217, 224, 309, 312, 331, 447, 618, 630, 708, 730, 773, 779, 815, 847, 872
Top metros and their area codes
Below are the primary cities in Illinois and the area codes that serve each metro. Cities with multiple codes share geography due to overlay assignments added as demand grew.
- Aurora — 331 , 630
- Chicago — 312 , 730 , 773 , 872
- Cicero — 708
- East St. Louis — 618
- Evanston — 224 , 847
- Peoria — 309
- Rockford — 779 , 815
- Springfield — 217 , 447
Illinois area code coverage by region
This regional breakdown maps each Illinois area code to the part of the state it serves. Illinois's codes split across 10 regions — pick the code that matches the area you want to reach.
- Central Illinois — area codes: 217, 447 (Springfield)
- Chicago — area code: 872 (Chicago)
- Chicago (non-Loop) — area code: 773 (Chicago)
- Downtown Chicago — area code: 312 (Chicago)
- Northern Chicago Suburbs — area codes: 224, 847 (Evanston)
- Northern Illinois — area codes: 779, 815 (Rockford)
- Southern Chicago Suburbs — area codes: 708, 730 (Cicero, Chicago)
- Southern Illinois — area code: 618 (East St. Louis)
- West-Central Illinois — area code: 309 (Peoria)
- Western Chicago Suburbs — area codes: 331, 630 (Aurora)
Why get a local Illinois number?
A Illinois area code number gives your business three core advantages:
- Local trust signal. Customers in Illinois recognize local area codes as their own. A familiar caller ID builds immediate credibility for service businesses, sales teams, and patient communication.
- Higher answer rate. Calls from a local area code are answered far more often than toll-free or out-of-area numbers — industry data puts the lift at 20–40%. That difference matters most for outbound sales, appointment confirmations, and service callbacks.
- Targeted marketing. Advertising a local Illinois number on print, radio, digital, and outdoor channels converts better than a national 800 number for audiences who prefer doing business locally.
How to get a Illinois area code number with DialPhone
Setting up a Illinois business number takes under 10 minutes:
- Sign up for a DialPhone plan. Choose any plan starting at $24/user/month. Free 14-day trial, no credit card required.
- Search available Illinois numbers. Filter the DialPhone number inventory by state, area code, city, or number pattern.
- Choose your number and configure. Assign your new Illinois number to a user or team, configure call routing, voicemail, AI receptionist, and business SMS.
- Port your existing number (optional). Already have a Illinois number? Free number porting completes in 2 to 5 business days with zero service interruption.
Compare Illinois area codes