Complete Guide to Illinois Phone Area Codes

Are you wondering what area code corresponds to your Illinois city? We’ll break it all down for you in this comprehensive post includes everything from historical area code changes to VoIP business solutions

From local users to virtual phone system seekers, knowing the dialing system across IL is essential for seamless contact and verification.

What Are Area Codes in Illinois?

Illinois telephone area codes identify specific geographic territories, supporting phone number management for personal and business use.

Structured by the NANP, the state of Illinois adheres to NANP’s numbering scheme. For official standards, visit NANPA’s website.

Illinois Area Code List

Find all the active codes below of Illinois area codes organized by coverage area:

• 217 – Central Illinois including Springfield
• 309 – Peoria, Bloomington, and western parts of IL
• 312 – Downtown Chicago only
• 773 – Northwest and South Side of Chicago
• 872 – Overlay for 312 and 773
• 847 – Northern suburbs including Evanston
• 224 – Overlay for 847
• 630 – Western suburbs
• 331 – Used in the same region
• 708 – Southwest Chicago suburbs
• 815 – Spans northern rural regions
• 779 – Same coverage region
• 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

Several trusted databases 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

Businesses operating in or targeting Illinois use local area codes to appear local and trustworthy in customers’ eyes.

Modern business platforms make it simple to buy Illinois area code updates or assign IL-based numbers.

If you're setting up a professional phone system with a local presence, explore business phone systems from Bling.

Overlay Area Codes in Illinois

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

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)

Overlay codes don’t replace old ones but coexist in the same region.

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

Here’s how the area codes are split by region in Illinois:

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.

Whether you're in downtown Chicago or remote southern Illinois, you can now get a local area code with VoIP solutions.

Buying an Illinois Local Business Number

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

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

You don’t need to be in Illinois physically—virtual systems handle routing through VoIP or PBX networks.

FAQ – Illinois Phone Codes