Illinois Area Codes Explained

Trying to understand which area code to use for your business in Illinois? We’ll break it all down for you in this comprehensive post dives into lookup tools, city-based breakdowns, and more.

Whether you're a resident, traveler, or business owner, grasping the phone number structure in Illinois is crucial for communication.

How Illinois Phone Codes Work

Area codes in Illinois are three-digit numbers assigned to different regions, supporting phone number management for personal and business use.

Structured by the NANP, Illinois area codes follow a format shared across the U.S. and Canada. For official standards, visit NANPA’s website.

Current List of Illinois Area Codes

Here is a breakdown of Illinois area codes organized by coverage area:

• 217 – Covers Springfield, Champaign, and surrounding areas
• 309 – Western central Illinois
• 312 – Central Chicago zone
• 773 – Northwest and South Side of Chicago
• 872 – Covers greater Chicago metro
• 847 – Northern suburbs including Evanston
• 224 – Overlay for 847
• 630 – Western suburbs
• 331 – Overlay for 630
• 708 – Southwest Chicago suburbs
• 815 – Rockford and northern IL
• 779 – Overlay for 815
• 464 – Launched to support number exhaustion

To learn more about official overlays and numbering plans, visit the FCC Area Code Resources.

How to Lookup Illinois Area Codes

There are many reliable lookup tools that help you identify the area code for a city or trace a phone call.

1. TrueCaller – Reverse lookup and spam detection
2. Whitepages – Detailed contact search and verification
3. Nomorobo – Great for spam and robocall filtering
4. YouTube: Illinois Area Codes Explained – Helpful visual resource
5. Wikipedia List – See historical and current Illinois codes

Using Illinois Phone Codes for Business Presence

Companies looking to reach customers in Illinois often opt for local numbers to appear local and trustworthy in customers’ eyes.

With services like Bling Cloud, businesses can instantly activate virtual numbers for any Illinois region.

If you're setting up a professional phone system with click here a local presence, explore Illinois-based VoIP services from Bling.

Illinois Area Code Overlays

Many IL area codes now have overlays due to high population and business growth.

Here are the main overlays:

• 872 – Overlays 312 and 773 (Chicago)
• 464 – Newest overlay for 708 (Chicago suburbs)
• 224 – Overlays 847 (Northern suburbs)
• 331 – Overlays 630 (Western suburbs)
• 779 – Overlays 815 (Northern Illinois)

Users must now dial 10 digits, even for local calls, due to overlays.

Regional Breakdown: Northern, Central, and Southern Illinois Area Codes

Phone area codes in Illinois follow regional distributions across the state.

Northern Illinois

• 312, 773, 872 – Chicago metro|Downtown and metro Chicago
• 847, 224 – Evanston, Waukegan, North Shore|Northern suburbs
• 630, 331 – Naperville, Wheaton, Oak Brook|Western suburbs
• 708, 464 – Cicero, Oak Lawn, South suburbs
• 815, 779 – Rockford, Joliet, Kankakee

Central Illinois

• 217 – Springfield, Urbana, Decatur
• 309 – Peoria, Bloomington, Galesburg

Southern Illinois

• 618 – East St. Louis, Carbondale, Belleville

How VoIP Is Changing Illinois Phone Systems

With the rise of cloud calling, VoIP is becoming the preferred method for phone communication in Illinois.

This flexibility helps businesses scale, reach target markets, and streamline support.

Get a Business Number with an Illinois Area Code

Getting a business phone number with an Illinois area code enhances regional credibility.

For example, Illinois business line instantly connects you with your target region.

It’s also scalable for multiple team members and departments.

FAQ – Illinois Phone Codes