Illinois Area Codes Explained

Need to identify or obtain an Illinois-based phone number? We’ll break it all down for you in this comprehensive post includes everything from historical area code changes to VoIP business solutions

Whether you're a resident, traveler, or business owner, understanding Illinois’ telephone code system is crucial for communication.

What Are Area Codes in Illinois?

Area codes in Illinois are three-digit numbers click here assigned to different regions, helping manage number allocation across cities.

Supervised by NANPA and the FCC,, Illinois codes align with the NANP guidelines used across North America. For official standards, visit NANPA’s website.

Illinois Area Code List

Below is a current list of the current area codes used across Illinois:

• 217 – Central Illinois including Springfield
• 309 – Peoria, Bloomington, and western parts of IL
• 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 – Spans northern rural regions
• 779 – Same coverage region
• 464 – Newest overlay for Chicago

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

Illinois Area Code Search Tools

There are many reliable lookup tools to discover which city an area code belongs to.

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.

Modern business platforms make it simple to buy or assign IL-based numbers.

Looking to get started? Check out Bling’s virtual number options today.

Overlay Area Codes in Illinois

To prevent exhaustion of available numbers, Illinois has implemented overlays in many regions.

These are the current overlays used in Illinois:

• 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)

Each overlay covers the same geographic region as the original area code.

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

Illinois is divided into three primary telephone regions: North, Central, and South.

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

Illinois Area Codes & VoIP Technology

Voice over IP (VoIP) services have revolutionized how people and businesses use area codes.

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

How to Get a Local Number in Illinois

It also helps with branding, geo-targeting, and customer service.

You can register a business phone number with any Illinois code through platforms like Bling.

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

Illinois Area Code: Common Questions Answered