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Area Code 331 Location & Details

State / Region: Illinois • Country: United States

Major Cities Covered: Aurora, Naperville, Schaumburg, Bolingbrook, Wheaton, Downers Grove, Elmhurst, Lombard, Bartlett, Oswego

Standard Dial Format
+1 (331) XXX-XXXX
Country Code: +1 (NANP Format)
What State is Area Code 331?
IllinoisState Hub →
Country Territory
United States
331 Area Code Time Zone
Central
331 Overlay Codes
630

Area Code 331 Geographic Map

Interactive location bounds and coverage area for Illinois (Central Timezone)

Lat: 41.84° • Lng: -88.15°
📍 Geographic Center: IllinoisMap data © OpenStreetMap contributors

Where is Area Code 331 Located?

Telephone area code 331 is assigned to Illinois in United States. It serves cities and metropolitan communities including Aurora, Naperville, Schaumburg, Bolingbrook, Wheaton, Downers Grove, Elmhurst, Lombard, Bartlett, Oswego.

Historical Context & Area Code Overlay Information:331 serves Illinois (United States).

For local and long-distance calls within area code 331, standard 10-digit dialing (331) XXX-XXXX applies.

Who Called Me from Area Code 331?

Received an unknown call, missed call, or text scam from area code 331? Here is how to trace who is calling from 331 area code and verify unknown numbers safely:

1.
Identify Missed Calls & Voicemails:

Legitimate contacts usually leave a detailed voicemail or caller ID record.

2.
Watch Out for Neighbor Spoofing:

Robocallers often fake incoming caller ID numbers using your local 331 prefix to boost pick-up rates.

3.
Reverse Phone Lookup Area Code 331:

Search public white-pages or use caller intelligence guides before returning unfamiliar calls.

Learn How Reverse Phone Lookups Work→

How to Call Area Code 331 & Dialing Format

When placing a phone call to a number in area code 331, follow the correct dialing format depending on your calling location:

  • Calling from inside the US / Canada (+1): Dial 1 + (331) + 7-digit number.
  • Calling from an international location outside +1: Dial your country's international exit code (e.g. 011 in US or + on mobile) + 1 + 331 + 7-digit number.
  • Do I need to dial area code 331 for local calls? Yes, 10-digit dialing (area code + line number) is mandatory across North American telephone networks.

Top Cities & Municipalities Served in Area Code 331

Urban centers, census places, and communities within the +1-331 calling area

50 Major Cities Listed
City NameCountyPopulation% of 331 Pop
AuroraDuPage County181,50511.9%
NapervilleDuPage County153,11410.0%
SchaumburgDuPage County77,2495.1%
BolingbrookDuPage County74,8034.9%
WheatonDuPage County54,0653.5%
Downers GroveDuPage County50,3653.3%
ElmhurstDuPage County46,1113.0%
LombardDuPage County44,3992.9%
BartlettDuPage County40,8552.7%
OswegoKendall County39,9482.6%
Carol StreamDuPage County39,3152.6%
StreamwoodDuPage County38,2772.5%
Hanover ParkDuPage County36,5682.4%
AddisonDuPage County35,7582.3%
WoodridgeDuPage County34,0282.2%
St. CharlesKane County33,5942.2%
Glendale HeightsDuPage County32,6552.1%
Glen EllynDuPage County28,7501.9%
YorkvilleKendall County26,7301.8%
BataviaKane County26,5861.7%

Counties Covered by Area Code 331

Geographic county distribution and population coverage across Illinois

County NameTotal Population% of 331 Area% of County
DuPage County932,65183.1%100%
Kane County523,4308.6%25%
Kendall County143,1256.6%71%
Will County708,9801.6%4%

☎️Area Code 331 Exchange Prefixes & Carriers

Showing 50 of 238 central office 3-digit prefixes and assigned telecom carriers

32% Landline42% Wireless25% VoIP
PrefixLine UsageRate CenterAssigned CarrierAssign Date
(331) 200-📱WirelessBARTLETTT-MOBILE USA, INC.07/11/2011
(331) 201-📱WirelessDOWNERSGRVCELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL01/06/2012
(331) 202-📱WirelessELMHURSTT-MOBILE USA, INC.01/17/2012
(331) 203-📱WirelessAURORAT-MOBILE USA, INC.10/12/2011
(331) 204-💻VoIPNAPERVILLEONVOY, LLC12/10/2015
(331) 205-📱WirelessAURORAT-MOBILE USA, INC.10/21/2011
(331) 206-📱WirelessAURORAT-MOBILE USA, INC.10/12/2011
(331) 207-📞LandlineYORKVILLELEVEL 3 COMMUNICATIONS, LLC - IL11/01/2011
(331) 208-📞LandlineAURORALEVEL 3 COMMUNICATIONS, LLC - IL11/08/2011
(331) 209-📞LandlineELMHURSTLEVEL 3 COMMUNICATIONS, LLC - IL01/17/2012
(331) 210-💻VoIPST CHARLESPEERLESS NETWORK OF ILLINOIS, LLC - IL03/06/2012
(331) 211-📞LandlineILMULTIPLE OCN LISTINGN/A
(331) 212-📞LandlineAURORAMCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL04/05/2012
(331) 213-📱WirelessNAPERVILLECELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL09/06/2011
(331) 214-📱WirelessDOWNERSGRVCELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL06/20/2012
(331) 215-📱WirelessNAPERVILLECELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL09/28/2012
(331) 216-📱WirelessOSWEGONEW CINGULAR WIRELESS PCS, LLC - IL10/31/2012
(331) 217-💻VoIPLOMBARDONVOY, LLC07/11/2023
(331) 218-📱WirelessWHEATONT-MOBILE USA, INC.07/09/2013
(331) 219-📞LandlineAURORATELNYX LLC03/16/2017
(331) 220-📱WirelessAURORAT-MOBILE USA, INC.07/12/2011
(331) 221-📞LandlineELMHURSTILLINOIS BELL TEL CO01/21/2009
(331) 222-📱WirelessST CHARLESNEW CINGULAR WIRELESS PCS, LLC - IL10/28/2008
(331) 223-📱WirelessST CHARLESNEW CINGULAR WIRELESS PCS, LLC - IL10/28/2008
(331) 224-💻VoIPITASCAONVOY, LLC06/05/2023
(331) 225-📱WirelessELMHURSTT-MOBILE USA, INC.08/22/2011
(331) 226-📱WirelessNAPERVILLET-MOBILE USA, INC.03/20/2017
(331) 227-📱WirelessSUGARGROVECELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL05/17/2016
(331) 228-📞LandlineST CHARLESPAETEC ITEL, LLC09/21/2011
(331) 229-📱WirelessNAPERVILLECELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL11/27/2012
(331) 230-📱WirelessAURORAT-MOBILE USA, INC.04/05/2017
(331) 231-📱WirelessNAPERVILLENEW CINGULAR WIRELESS PCS, LLC - IL08/07/2017
(331) 232-📱WirelessW CHICAGONEW CINGULAR WIRELESS PCS, LLC - IL08/08/2017
(331) 233-📞LandlineDOWNERSGRVTELNYX LLC03/13/2017
(331) 234-📱WirelessSUGARGROVECELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL07/08/2013
(331) 235-📱WirelessST CHARLESNEW CINGULAR WIRELESS PCS, LLC - IL10/17/2017
(331) 236-📱WirelessWHEATONT-MOBILE USA, INC.04/05/2017
(331) 237-📞LandlineNAPERVILLEMCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL11/07/2017
(331) 238-📞LandlineDOWNERSGRVTELEPORT COMMUNICATIONS AMERICA, LLC - IL12/19/2017
(331) 239-💻VoIPYORKVILLEONVOY, LLC08/27/2018
(331) 240-💻VoIPW CHICAGOPEERLESS NETWORK OF ILLINOIS, LLC - IL04/10/2013
(331) 241-💻VoIPLOMBARDONVOY, LLCN/A
(331) 242-📱WirelessLOMBARDT-MOBILE USA, INC.10/19/2018
(331) 243-📱WirelessLOMBARDT-MOBILE USA, INC.10/19/2018
(331) 244-💻VoIPNAPERVILLEONVOY, LLC09/21/2017
(331) 245-📱WirelessBARTLETTT-MOBILE USA, INC.04/18/2013
(331) 246-📱WirelessLEMONTT-MOBILE USA, INC.10/19/2018
(331) 247-📞LandlineNAPERVILLEVONAGE AMERICA LLC11/21/2018
(331) 248-📞LandlineGENEVACOMCAST IP PHONE, LLC07/06/2007
(331) 249-💻VoIPNAPERVILLEONVOY, LLC12/05/2018

Frequently Asked Questions about Area Code 331

Where is area code 331 located?

Area code 331 is located in Illinois (United States), serving cities like Aurora, Naperville, Schaumburg, Bolingbrook, Wheaton, Downers Grove, Elmhurst, Lombard, Bartlett, Oswego.

What timezone is area code 331?

Area code 331 operates in the Central timezone.

What state is area code 331?

Area code 331 is assigned to the state / telecom territory of Illinois.

Is area code 331 a scam or dangerous?

Area code 331 is an official geographic area code for Illinois. However, beware of robocaller spoofing.

Illinois State Area Codes

View complete directory of telephone area codes assigned to Illinois.

Explore Illinois Directory

Get a 331 Business Phone Number

How to acquire a virtual phone number or business line with area code 331 for local customer trust in Illinois.

Get 331 Business Number
🛡️ Scam & Safety Directory

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Overlay & Nearby Area Codes for Illinois

Explore neighboring telecom prefixes sharing geographical boundaries with area code 331.

630
Central
Area Code 630
Aurora, Naperville, Schaumburg, Bolingbrook, Wheaton, Downers Grove, Elmhurst, Lombard, Bartlett, Oswego
217
Central
Area Code 217
Springfield, Champaign, Decatur, Urbana, Quincy, Danville, Jacksonville, Charleston, Mattoon, Chatham
224
Central
Area Code 224
Elgin, Waukegan, Schaumburg, Evanston, Arlington Heights, Skokie, Palatine, Des Plaines, Mount Prospect, Hoffman Estates
309
Central
Area Code 309
Peoria, Bloomington, Normal, Moline, Romeoville, Rock Island, Pekin, Galesburg, East Peoria, Crest Hill
312
Central
Area Code 312
Chicago, West Chicago
447
Central
Area Code 447
Springfield, Champaign, Decatur, Urbana, Quincy, Danville, Jacksonville, Charleston, Mattoon, Chatham