Illinois Area Codes Explained

Are you wondering what area code corresponds to your Illinois city? This detailed guide dives into lookup tools, city-based breakdowns, and more.

From local users to virtual phone system seekers, understanding Illinois’ telephone code system helps with routing calls, marketing, and compliance.

How Illinois Phone Codes Work

Illinois telephone area codes identify specific geographic territories, helping manage number allocation across cities.

Supervised by NANPA and the FCC,, Illinois area codes follow a format shared across the U.S. and Canada. For official standards, visit NANPA’s website.

Illinois Area Code List

Here is a breakdown showing city coverage and overlays:

• 217 – Central Illinois including Springfield
• 309 – Peoria, Bloomington, and western parts of IL
• 312 – Downtown Chicago only
• 773 – Rest of Chicago outside downtown
• 872 – Covers greater Chicago metro
• 847 – North Chicago suburbs
• 224 – Overlay for 847
• 630 – Western suburbs
• 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.

Illinois Area Code Search Tools

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

Using Illinois Phone Codes for Business Presence

Businesses operating in or targeting Illinois use local area codes to establish trust, improve response rates, and localize presence.

Using VoIP and virtual phone systems, getting a number with an Illinois area code is now easy and affordable.

If you're setting up a professional phone system with a local presence, explore Illinois-based VoIP services from Bling.

Overlay Area Codes in Illinois

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

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 here 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

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.

How to Get a Local Number in Illinois

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

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.

FAQ – Illinois Phone Codes