What time zone is area code 312 in?

Area code 312 uses Central Time.

What area codes overlay 312?

872 serves the same area as 312. New numbers in the area can get any of these codes, which is why local calls need all 10 digits.

Is a call from area code 312 a scam?

The area code alone doesn’t tell you. Most calls from 312 are ordinary local calls, but scammers can fake (“spoof”) any number. If you don’t recognize a 312 number, let it go to voicemail.

Can a 312 number be outside Illinois?

Yes. People keep their numbers when they move and when they switch to mobile or internet phone services, so a 312 caller can be anywhere.

Area code 312

Where is area code 312?

Chicgozn01, Wheeling and Oak Brook, Illinois

Local time: … (Central Time)

State	Illinois
Country	United States
Main cities	Chicgozn01, Wheeling and Oak Brook
Time zone	Central Time
Overlay area codes	872
In service since	1947
Assigned prefixes	784
Dialing format	(312) XXX-XXXX · +1 312 XXX XXXX from abroad

Look up a 312 number

Cities and towns in area code 312

Listed by how many phone prefixes (the 3 digits after the area code) are assigned to each place in 312.

Chicgozn01, IL (746)
Wheeling, IL (12)
Oak Brook, IL (11)
La Grange, IL (8)
Northbrook, IL (3)
Schaumburg, IL (2)
Chicgozn04, IL (1)
Chicgozn07, IL (1)

Phone companies in area code 312

The carriers that hold the most 312 prefixes. People can move their number to another carrier, so this shows who first issued a number, not who serves it today.

Prefixes	Carrier
334	Illinois Bell Tel Co (AT&T)
82	New Cingular Wireless PCS (AT&T)
64	T-Mobile USA
54	Verizon Wireless
40	Mcimetro Access Transmission Services
33	Level 3 Communications
33	Spok
22	Teleport Communications America

All 784 prefixes in area code 312

Pick the 3 digits after the area code to see that prefix’s city and carrier.

Area codes that overlay 312

Questions

Where is area code 312?: Area code 312 is in Illinois. It serves Chicgozn01, Wheeling, Oak Brook, La Grange and Northbrook and 3 other cities and towns.
What time zone is area code 312 in?: Area code 312 uses Central Time.
What area codes overlay 312?: 872 serves the same area as 312. New numbers in the area can get any of these codes, which is why local calls need all 10 digits.
Is a call from area code 312 a scam?: The area code alone doesn’t tell you. Most calls from 312 are ordinary local calls, but scammers can fake (“spoof”) any number. If you don’t recognize a 312 number, let it go to voicemail.
When did area code 312 start?: 312 went into service in 1947.
Can a 312 number be outside Illinois?: Yes. People keep their numbers when they move and when they switch to mobile or internet phone services, so a 312 caller can be anywhere.

Other area codes in Illinois

Area code	Main cities
217	Springfield, Champaign and Decatur
224	Northbrook, Arlington Hts and Des Plaines
309	Peoria, Bloomington and Rock Island
331	Aurora, Naperville and Downers Grove
447	Danville, Springfield and Champaign
464	Oak For So, Forest Park and La Grange
618	Collinsville, Carbondale and Belleville
630	Schaumburg, La Grange and Naperville
708	La Grange, Chicago Heights and Oak Forest
730	Centralia, Herrin and Belleville
773	Harwood Heights, Chicgozn01 and Chicgozn02
779	Rockford, Joliet and Momence
815	Rockford, Joliet and Kankakee
847	Northbrook, Schaumburg and Arlington Hts
861	Peoria, Danvers and Moline