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.

No matter if you’re launching a business or tracing a call, understanding Illinois’ telephone code system helps with routing calls, marketing, and compliance.

What Are Area Codes in Illinois?

The area code system in Illinois segments regions for organized call routing, allowing calls to be directed accurately.

Administered by the North American Numbering Plan Administration (NANPA),, the state of Illinois adheres to NANP’s numbering scheme. For official standards, visit NANPA’s website.

Illinois Area Code List

Here is a breakdown 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 – Covers greater Chicago metro
• 847 – Northern suburbs including Evanston
• 224 – Also covers northern suburbs
• 630 – Covers DuPage County, Naperville, Wheaton
• 331 – Overlay for 630
• 708 – Southwest Chicago suburbs
• 815 – Rockford and northern IL
• 779 – Same coverage region
• 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

Several trusted databases 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

Illinois Virtual Numbers for Businesses

Companies looking to reach customers in Illinois often opt for local numbers to boost call pick-up rates and brand visibility.

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 a local presence, explore cloud phone platforms from Bling.

Overlay Area Codes in Illinois

To prevent exhaustion of available more info 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)

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

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

Impact of VoIP on Illinois Numbers

VoIP lets you use any area code in Illinois without a physical presence.

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

Get a Business Number with an Illinois Area Code

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.

FAQ – Illinois Phone Codes