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Area Code 312 Location & Details

State / Region: Illinois • Country: United States

Major Cities Covered: Chicago, West Chicago

Standard Dial Format
+1 (312) XXX-XXXX
Country Code: +1 (NANP Format)
What State is Area Code 312?
IllinoisState Hub →
Country Territory
United States
312 Area Code Time Zone
Central
312 Overlay Codes
872

Area Code 312 Geographic Map

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

Lat: 41.87° • Lng: -87.95°
📍 Geographic Center: IllinoisMap data © OpenStreetMap contributors

Where is Area Code 312 Located?

Telephone area code 312 is assigned to Illinois in United States. It serves cities and metropolitan communities including Chicago, West Chicago.

Historical Context & Area Code Overlay Information:312 serves Illinois (United States).

For local and long-distance calls within area code 312, standard 10-digit dialing (312) XXX-XXXX applies.

Who Called Me from Area Code 312?

Received an unknown call, missed call, or text scam from area code 312? Here is how to trace who is calling from 312 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 312 prefix to boost pick-up rates.

3.
Reverse Phone Lookup Area Code 312:

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

Learn How Reverse Phone Lookups Work→

How to Call Area Code 312 & Dialing Format

When placing a phone call to a number in area code 312, follow the correct dialing format depending on your calling location:

  • Calling from inside the US / Canada (+1): Dial 1 + (312) + 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 + 312 + 7-digit number.
  • Do I need to dial area code 312 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 312

Urban centers, census places, and communities within the +1-312 calling area

2 Major Cities Listed
City NameCountyPopulation% of 312 Pop
ChicagoCook County2,731,58599.1%
West ChicagoDuPage County25,2960.9%

Counties Covered by Area Code 312

Geographic county distribution and population coverage across Illinois

County NameTotal Population% of 312 Area% of County
Cook County5,188,79199.1%53%
DuPage County932,6510.9%3%

☎️Area Code 312 Exchange Prefixes & Carriers

Showing 50 of 799 central office 3-digit prefixes and assigned telecom carriers

68% Landline26% Wireless6% VoIP
PrefixLine UsageRate CenterAssigned CarrierAssign Date
(312) 200-📱WirelessCHICGOZN01METROPCS, INC.10/02/2017
(312) 201-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 202-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 203-📱WirelessCHICGOZN01NEW CINGULAR WIRELESS PCS, LLC - ILN/A
(312) 204-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 205-📞LandlineCHICGOZN01MCIMETRO ACCESS TRANSMISSION SERVICES LLCN/A
(312) 206-📱WirelessCHICGOZN01NEW CINGULAR WIRELESS PCS, LLC - ILN/A
(312) 207-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 208-📱WirelessCHICGOZN01NEW CINGULAR WIRELESS PCS, LLC - ILN/A
(312) 209-📱WirelessNORTHBROOKCELLCO PARTNERSHIP DBA VERIZON WIRELESS - ILN/A
(312) 210-💻VoIPCHICGOZN01PEERLESS NETWORK OF ILLINOIS, LLC - ILN/A
(312) 211-📞LandlineXXXXXXXXXXMULTIPLE OCN LISTINGN/A
(312) 212-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 213-📱WirelessCHICGOZN01NEW CINGULAR WIRELESS PCS, LLC - ILN/A
(312) 214-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 215-📱WirelessWHEELINGNEW CINGULAR WIRELESS PCS, LLC - ILN/A
(312) 216-📞LandlineCHICGOZN01FIRST COMMUNICATIONS, LLC02/13/2012
(312) 217-📱WirelessCHICGOZN01T-MOBILE USA, INC.N/A
(312) 218-📱WirelessCHICGOZN01NEW CINGULAR WIRELESS PCS, LLC - ILN/A
(312) 219-💻VoIPCHICGOZN01BANDWIDTH.COM CLEC, LLC - IL04/10/2012
(312) 220-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 221-📱WirelessCHICGOZN01T-MOBILE USA, INC.06/17/2011
(312) 222-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 223-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 224-📞LandlineCHICGOZN01LEVEL 3 COMMUNICATIONS, LLC - ILN/A
(312) 225-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 226-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 227-📞LandlineCHICGOZN01ILLINOIS BELL TEL CO09/15/2010
(312) 228-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 229-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 230-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 231-📱WirelessROSELLENEW CINGULAR WIRELESS PCS, LLC - ILN/A
(312) 232-📞LandlineCHICGOZN01AMERICAN MESSAGING SERVICES, LLC04/23/2001
(312) 233-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 234-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 235-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 236-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 237-📱WirelessCHICGOZN01CELLCO PARTNERSHIP DBA VERIZON WIRELESS - ILN/A
(312) 238-📞LandlineCHICGOZN01LEVEL 3 COMMUNICATIONS, LLC - ILN/A
(312) 239-📞LandlineCHICGOZN01AT&T - LOCALN/A
(312) 240-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 241-📱WirelessCHICGOZN01NEW CINGULAR WIRELESS PCS, LLC - IL08/17/2011
(312) 242-📞LandlineCHICGOZN01TELEPORT COMMUNICATIONS AMERICA, LLC - ILN/A
(312) 243-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 244-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 245-📞LandlineCHICGOZN01ILLINOIS BELL TEL CON/A
(312) 246-📱WirelessWHEELINGNEW CINGULAR WIRELESS PCS, LLC - ILN/A
(312) 247-📞LandlineCHICGOZN01FIRST COMMUNICATIONS, LLC04/06/2004
(312) 248-📱WirelessCHICGOZN01METROPCS, INC.07/01/2014
(312) 249-📞LandlineCHICGOZN01SPOK, INC.N/A

Frequently Asked Questions about Area Code 312

Where is area code 312 located?

Area code 312 is located in Illinois (United States), serving cities like Chicago, West Chicago.

What timezone is area code 312?

Area code 312 operates in the Central timezone.

What state is area code 312?

Area code 312 is assigned to the state / telecom territory of Illinois.

Is area code 312 a scam or dangerous?

Area code 312 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 312 Business Phone Number

How to acquire a virtual phone number or business line with area code 312 for local customer trust in Illinois.

Get 312 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 312.

872
Central
Area Code 872
Chicago
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
331
Central
Area Code 331
Aurora, Naperville, Schaumburg, Bolingbrook, Wheaton, Downers Grove, Elmhurst, Lombard, Bartlett, Oswego
447
Central
Area Code 447
Springfield, Champaign, Decatur, Urbana, Quincy, Danville, Jacksonville, Charleston, Mattoon, Chatham