Area code 331 covers Aurora and surrounding areas in Illinois. It was activated in 2007 as an overlay of area code 630. For the full picture, see all Illinois area codes.
| State | Illinois |
|---|---|
| Primary city | Aurora |
| Cities also served | Aurora, Naperville, Wheaton, Bolingbrook, Downers Grove, Elmhurst, Lombard, Bartlett |
| Time zone | Central (UTC-6 / UTC-5 DST) |
| Year established | October 7, 2007 |
| Original 1947 NPA? | No |
| Parent code | 630 |
| Overlay codes | 630 |
| Currently in use? | Yes, actively assigned |
| Ten-digit dialing required? | Yes |
Cities Served by Area Code 331
Area code 331 serves Chicago western suburbs — DuPage, Kane, Will, Cook, and Kendall counties, including the following cities and communities:
- Aurora
- Naperville
- Wheaton
- Bolingbrook
- Downers Grove
- Elmhurst
- Lombard
- Bartlett
Nearby area codes covering the same broader region include: 630, 708, 224, 847, 312, 773, 872, 815, 779.
How to Get a 331 Phone Number
There are three ways to get a phone number with the 331 area code, each suited to a different need:
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Browse 331 Numbers →- Buy from a premium-number specialist. Companies that hold curated inventories of specific area codes can sell you a 331 number directly, often with a one-time fee and ownership transferred to you (no recurring carrier fees). This is the option for picking a specific memorable number, or for getting an area code that most carriers won’t let you request. Browse our 331 inventory.
- Sign up with a VoIP carrier. Voice-over-IP services (such as Google Voice, OpenPhone, Grasshopper, and many others) can typically provision a 331 number on request, especially for active overlay codes. You won’t usually get to pick the specific number, but you’ll get a working line in the area code. This is the cheapest option for anyone who doesn’t need a particular number.
- Port an existing 331 number. If you already have a 331 phone number with another carrier, you can transfer it (port it) to a new service provider while keeping the number. This works for landlines, cell phones, and VoIP services, though landlines outside of Illinois sometimes can’t accept inbound ports of 331 numbers due to 911 routing rules.
Looking for a 331 number? 212areacode.com offers premium 331 numbers for Aurora, Illinois — choose your number, port it to any carrier in 3–5 business days, and pay a one-time fee with no monthly charges. Browse available 331 numbers →
Frequently Asked Questions
Is the 331 area code still in use?
Yes. 331 is actively assigned to new phone lines in Chicago western suburbs — DuPage, Kane, Will, Cook, and Kendall counties.
What is the difference between 331 and 630?
Today they share the same geographic territory in Illinois. New phone lines in the area may be assigned either code. The two codes work identically for calling, billing, and service.
What is the parent area code of 331?
Area code 331 is an overlay of 630. Both codes serve the same region of Illinois.
Can I get a 331 number if I don't live in Illinois?
Yes. Phone numbers are no longer tied to a physical address. With VoIP service or a number broker, you can hold a 331 number from anywhere in the world. The number routes to whatever device or carrier you specify.
Is 331 a scam area code?
No. 331 is a legitimate, active area code for Chicago western suburbs — DuPage, Kane, Will, Cook, and Kendall counties. Like any area code, scammers occasionally spoof 331 caller IDs, but the code itself is heavily used by real Illinois businesses, government offices, and residents.
What cities are in the 331 area code?
Area code 331 covers dozens of communities across DuPage, Kane, Will, Cook, and Kendall counties, including Aurora, Naperville, Wheaton, Bolingbrook, Downers Grove, Elmhurst, Lombard, and Bartlett.
Is 331 an overlay of another area code?
Yes. Area code 331 is an overlay of area code 630, introduced on October 7, 2007. Both codes serve the exact same geographic region in Chicago’s western suburbs, and ten-digit dialing is required for all calls in the area.
Where did area code 630 come from?
Area code 630 was created on August 3, 1996, in a three-way split of area code 708. When 630 neared exhaustion from suburban growth and mobile phone proliferation, area code 331 was added as an overlay in 2007.
Related Reading
- Why Use Area Codes For Local Calls?
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- How Do Area Codes Work?
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