312 area code History, map, countries Detail


The 312 area code is a telephone exchange code assigned to the city of Chicago, Illinois, United States. It was created in 1947 and has since remained unchanged.

What is the 312 area code?

This is unique because it is the only in North America that uses the same prefixes as other countries. This means that calling someone from that and requires international callers to dial 011 + country code + 312 + phone number.

The 312 area code contains all or part of:  

312 Area code


The 312 area code was created in 1947 from the original Chicago telephone exchange. The first digit of the phone number, 2, is used to indicate a central office (CO), and 3 indicates an outside plant connection. At one time, there were three COs served by this code, but they are now consolidated into one central office located at 2300 S. California Avenue in Chicago. In addition, it includes the greater Chicagoland area, including most of Cook County. Its same recognized like 334, 335.

312 Area code

As of July 1, 2015, there are approximately 4.9 million telephones within the area. Of these numbers, about 80% are residential lines, while the remaining 20% are business lines.

 Where 312 Area code is located?

Area code 312 is used by the city of Chicago, which includes the downtown area and its immediate surroundings. The plan area is entirely surrounded by 703, which serves the rest Chicago. Both are overlayed which is why they look similar.

312 Area code location map

312 Area code map
Read about : 323 Area code

Is 312 area code a scam?

No it’s not a scam. It’s only use for the purpose of business communication between the users and the business companies representatives. Sometime scammers and fraudulent try to scare people by asking personal information . So this code helps to recognize the numbers.

312 area code time zone

Area code 312 lies within the Central Time Zone.

How to call a 312 Area code Phone Number?

To call a phone number with 312, dial 011-312-XXXXX. For example, if you wanted to call the number 623-555-5555, you would dial 011-312 -623-555-5555. If you need more help dialing your 312 code phone number, check out our How To Call section.

Caller ID:

You can see who’s calling before answering. If caller id shows unknown then just ignore them.

International Dialing Code:

For making calls internationally dial 011 + country code + 312 + phone number without any leading zero. For Example:- Calling from USA to UK dial 011 44 instead of 01144.

Top Counties in Area Code 312

CountyTotal Population% of 312% of County
Cook, IL4,273,675100%1.5%

Top Cities in Area Code 312

CityTotal Population% of 312% of City
Chicago, IL2,584,488100%8.8%

Frequently Asked Questions

Calling 311 Area Code Numbers From Outside US?

Yes! You can directly call 311 numbers from anywhere in the world. Just dial the international access code i.e.- 00 followed by the destination country code.

What is the cost of a 312 Area code phone number?

The price of calling a number varies depending on different factors like when the call is being made etc. Check out the rates below!

Time Period – Cost

Weekdays 10 AM – 9 PM $0.10 per minute

Weekends / Holidays 10 AM – 9PM $0.15 per minute

24 Hours $0.30 per minute

What is the meaning of area code 312?

It refers to the Chicago Metropolitan Telephone Exchange. This exchange covers the entire metropolitan area that includes the city of Chicago as well as suburbs such as Arlington Heights, Bellwood, Brookfield, Burbank, Evanston, Glenview, Oak Park, Palos Hills, River Grove, Rolling Meadows, South Barrington, Westchester, Wheeling, Winnetka, Wood Dale, Zion, and others.

What is 312 area code?

312 area code is serving in the city of Chicago.

Why does my phone keep ringing when I enter an incorrect area code or prefix?

You may have entered an incorrect area code or a wrong prefix. In such cases, you will be asked to reenter the correct prefix. Please note that if your phone has been switched off, the caller will hear a busy tone. Also, please make sure that you don’t dial 911 when entering an incorrect dail.

Can I call a 312 area code phone number from outside United States?

Yes, you can call 312 area code phone number even from outside the U.S.

Can I call 312 numbers from other countries?

No, we do not provide international service at this time. We are always looking into ways to expand our services and provide better customer experience globally.


3 thoughts on “312 area code History, map, countries Detail”

Leave a Comment