Comprehensive Guide to Illinois Area Codes

Complete Guide to Illinois Phone Area Codes

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

No matter if you’re launching a business or tracing a call, knowing the dialing system across IL is crucial for communication.

What Are Area Codes in Illinois?

The area code system in Illinois segments regions for organized call routing, helping manage number allocation across cities.

Administered by the North American Numbering Plan Administration (NANPA),, Illinois area codes follow a format shared across the U.S. and Canada. For official standards, visit NANPA’s website.

Active Area Codes in IL

Here is a breakdown showing city coverage and overlays:

• 217 – Central Illinois including Springfield
• 309 – Western central Illinois
• 312 – Downtown Chicago only
• 773 – Northwest and South Side of Chicago
• 872 – Overlay for 312 and 773
• 847 – Northern suburbs including Evanston
• 224 – Also covers northern suburbs
• 630 – Covers DuPage County, Naperville, Wheaton
• 331 – Overlay for 630
• 708 – Oak Lawn, Cicero
• 815 – Rockford and northern IL
• 779 – Overlay for 815
• 464 – Newest overlay for Chicago

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 to find an Illinois area code by city or number.

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

Why Businesses Choose Local Illinois Numbers

Entrepreneurs and service providers rely on local numbers to establish trust, improve response rates, and localize presence.

Modern business platforms make it simple to buy 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

Illinois uses overlay area codes to handle the increasing demand for phone numbers.

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)

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

How VoIP Is Changing Illinois Phone Systems

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

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.

Frequently Asked Questions About Illinois Area Codes