Complete Guide to Illinois Phone Area Codes

Are you wondering what area code corresponds to your Illinois city? You’ve come to the right place—this blog includes everything from historical area code changes to VoIP business solutions

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

Understanding Illinois Area Codes

Illinois telephone area codes identify specific geographic territories, allowing calls to be directed accurately.

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

Illinois Area Code List

Below is a current list 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 – North Chicago suburbs
• 224 – Overlay for 847
• 630 – Covers DuPage County, Naperville, Wheaton
• 331 – Used in the same region
• 708 – Southwest Chicago suburbs
• 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.

Illinois Area Code Search Tools

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

Why Businesses Choose Local Illinois Numbers

Businesses operating in or targeting Illinois use local area codes 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.

Illinois Area Code Overlays

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

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 Illinois phone area codes 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

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.

Buying an Illinois Local Business Number

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

For example, get an Illinois-based number instantly connects you with your target region.

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

Illinois Area Code: Common Questions Answered