Aurora, Illinois
331 Area Code
Strengthen your presence in Aurora and Chicago's western suburbs with a 331 area code number. Perfect for businesses targeting DuPage, Kane and Will counties who want strong local recognition and higher answer rates.
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About 331 Area Code
Area code 331 serves Aurora, Naperville, Bolingbrook and Chicago's western suburbs. Introduced on October 7, 2007, as an overlay to the existing 630 area code, 331 covers major communities across DuPage, Kane, Will, Cook and Kendall counties. The code supports local voice and SMS numbers used by businesses, healthcare providers, educational institutions and manufacturers throughout the Fox Valley region.
The 331 region blends manufacturing strength (Aurora's industrial base), healthcare leadership (Edward Hospital in Naperville), retail commerce and technology sectors. Aurora is Illinois' second-largest city, while Naperville consistently ranks among the nation's best places to live. Businesses use 331 numbers for customer service, appointment scheduling, sales outreach and logistics coordination. Local numbers consistently generate higher answer rates than toll-free or out-of-area alternatives because they signal genuine regional presence.
FoneSwift displays real-time 331 inventory and capabilities on this page. Filter by Voice, SMS and MMS support to match your communication needs. Since 331 is an overlay of 630, both codes serve identical geographic areas. If 331 numbers are limited, consider the 630 code (same coverage area) or adjacent NPAs like 630, 708 or 815 for broader suburban Chicago reach.
If you're targeting western suburban Chicago customers, display numbers in both local and international formats (e.g., (331) 555-1234 and +1 331 555 1234) and register A2P messaging if planning business SMS campaigns. For porting existing numbers, see our porting guide. Many businesses retain their numbers long-term to maintain customer recognition and avoid updating marketing materials across multiple channels.
| Country | United States |
| State | Illinois |
| Area code | 331 |
| Primary cities | Aurora, Naperville, Bolingbrook, Wheaton, Downers Grove |
| Counties served | DuPage, Kane, Kendall, Cook, Will |
| Timezone | America/Chicago (CST) |
| Created | October 7, 2007 |
| International Format | +1 331 XXX XXXX |
| Local Format | (331) XXX-XXXX |
Ten-digit dialing is mandatory for all calls within the 630/331 region. Register A2P messaging for business SMS to comply with carrier 10DLC requirements.
Area code 331 uses Central Standard Time (CST, UTC-6) and observes Daylight Saving Time, shifting to Central Daylight Time (CDT, UTC-5) from March through November.
Local 331 numbers build suburban Chicago credibility and trust. If 331 inventory is limited, consider overlay code 630 (same geographic area) or adjacent codes like 708 or 815 for broader coverage while maintaining a Chicago-area presence.
Quick Facts about 331 Area Code
Interesting tidbits about this area code 331
City of Lights legacy
Aurora earned the nickname "City of Lights" in 1881 when it became one of the first U.S. cities to install an all-electric street lighting system, showcasing early technological innovation.
Overlay introduction
Area code 331 was created as an overlay for 630 in October 2007 to address number exhaustion in the rapidly growing western suburbs without requiring existing numbers to change.
Four-county city
Aurora is one of only three Illinois cities that spans four counties (Kane, DuPage, Kendall and Will), reflecting the region's complex suburban geography and growth patterns.
Top-ranked communities
Naperville has consistently ranked among Money Magazine's best places to live in America and was named the wealthiest Midwest city in a 2010 study, driving strong business demand.
Mandatory 10-digit dialing
Since the 331 overlay launch, all calls within the 630/331 region require 10-digit dialing (area code plus seven digits), even for local calls within the same area code.
Education hub
The region hosts multiple nationally recognized school districts including Indian Prairie School District 204, Naperville Community Unit School District 203, and several top-ranked universities.
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How Does Local 331 Phone Numbers Work?
A local business number is a structured telephone identifier that tells networks where to route calls and messages. When you use a 331 number in Aurora and Illinois, the digits signal the international gateway, the geographic region, the local exchange and the specific subscriber, so calls reach the right destination quickly and reliably.
The typical parts of a United States local number are:
- Country code (+1): identifies United States for international routing.
- Area code (331): directs the call to the Aurora / Illinois region.
- Central office / exchange (eg. 555): narrows the call to a local switching area or rate center.
- Subscriber number (eg. 1234): the unique line assigned to a person, extension, or device.
Example formats:
| International Format (E.164) | +1 331 555 1234 |
| Local Format (National) | (331) 555-1234 |
Quick Dialing Guide
The correct formats to reach 331 numbers locally and globally.
From Landlines
Standard United States FormatUse for domestic long-distance calls within United States.
From Mobile
E.164 InternationalThe universal format. Works on any mobile device, anywhere.
International
From abroadDialing from outside United States (exit code 00 varies by country).
With FoneSwift, your 331 number can be instantly configured through our intuitive dashboard. Connect it to call forwarding rules, AI voice agents, IVR menus, or route calls directly to any device. Enable voice, SMS, and MMS capabilities right from your account, no technical setup required. Your number becomes active immediately after purchase, and you can update routing, business hours, and integrations anytime.
For businesses, local numbers offer clear benefits: higher answer rates, stronger local recognition, and better performance for local campaigns and customer trust. Typical business features include call forwarding, call recording, auto-attendants, voicemail-to-email, and multi-device ringing.
Important operational notes:
- SMS & A2P: If you plan to send application-to-person messages from a 331 number, register your traffic where required and follow carrier rules (10DLC/A2P) to avoid deliverability or throughput issues.
- Number Porting: Bring your existing 331number to FoneSwift seamlessly. Our team handles the entire porting process, simply submit your number details and we'll coordinate with your current provider. Porting typically completes within 5-10 business days, and you'll receive updates at each step. There's no service interruption during the transfer.
- Display & formatting: Always publish numbers in both local and E.164 formats so international and mobile users can easily dial.
Ready to get started? Browse available 331 numbers in the phone numbers section above, you'll see real-time availability and can filter by features like voice, SMS, and MMS. Once you find your perfect number, purchase it in seconds and start making calls immediately. Our team is here to help you choose the right setup for your business needs, whether you're setting up AI receptionists, call forwarding, or SMS campaigns. Start your 14-day free trial today, no credit card required.
How to Get a 331 Phone Number
Buying a local 331 phone number using FoneSwift is easy and takes just a few minutes. Follow these simple steps to get your local 331 phone number and start connecting with customers in United States today.
Create a new account on FoneSwift or sign in to your existing account to get started.
Once logged in, you'll be taken to your FoneSwift dashboard where you can manage all your phone numbers and settings.
Click on Settings in the sidebar, then go to "My Numbers" and click the "Add a Number" button.
Choose United States as your country from the dropdown menu.
Select Local as the type of number, then choose the 331 area code from the available options.
Click the "Search" button to see all available phone numbers with the selected area code.
Browse through the available numbers, select one that fits your needs, click "Buy Number", and confirm your purchase.
Your number is now active! Start making and receiving calls from the FoneSwift Dialer immediately.
You can configure your number to handle calls, forward calls, or even create an AI voice agent to handle the calls for you.
Businesses Using 331 Phone Numbers
Chicago's western suburbs host manufacturing, healthcare, retail, education and professional services industries. Local 331 phone numbers support customer-facing operations and regional business relationships across DuPage, Kane and Will counties.
Manufacturing and industrial
Aurora's manufacturing sector includes food processing, precision equipment and industrial operations. Companies use 331 numbers for supplier coordination, quality control, logistics management and B2B sales.
Healthcare and medical services
Major healthcare systems like Edward Hospital, Advocate Health and specialty clinics use local numbers for appointment scheduling, patient outreach, telehealth services and emergency lines throughout DuPage and Kane counties.
Retail and e-commerce
Retail centers, shopping districts and e-commerce fulfillment operations use 331 numbers for customer service, order management, pickup notifications and local delivery coordination across suburban markets.
Education and training
Schools, colleges, training centers and tutoring services rely on local numbers for admissions, parent communication, student services and community outreach throughout the western suburbs.
Professional services
Law firms, accounting practices, financial advisors and consulting firms use 331 numbers to establish local credibility for client intake, appointment scheduling and professional consultation services.
Transportation and logistics
Distribution centers, freight companies and delivery services along the I-88 corridor use local numbers for driver dispatch, warehouse coordination, shipment tracking and customer notifications.
Why Choose 331 Local Phone Number for Your Business?
Discover the advantages of having a local phone number that builds trust, increases engagement, and drives results.
Powerful Features for Your 331 Local Phone Number
Get the most out of your localphone number with FoneSwift's enterprise-grade features designed to help your business communicate more effectively.
Nearby Area Codes
Explore other area codes in the same region to expand your local presence.
Frequently Asked Questions
What cities use the 331 area code?
When was the 331 area code created?
Can I get SMS-capable numbers in area code 331?
What is the difference between 331 and 630 area codes?
Do I need to dial 10 digits for 331 numbers?
Is 331 a toll-free code?
How do I buy a 331 local phone number?
Can I port my existing 331 number to FoneSwift?
Where can I find official information about area code 331?
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