The Ultimate Guide to the 312 Area Code
| Country | United States of America (USA) |
| State | Illinois |
| Major City | Chicago |
| Major County | Cook |
| Time Zone | Central Time Zone |
| Standard Time | UTC/GMT -6:00 hours |
| Daylight Saving Time | GMT/UTC -5:00 hours |
| ZIP Code | 60601-60699 |
What is Area Code 312?
The 312 area code is Chicago’s historic telephone code, established by the North American Numbering Plan Administrator (NANPA) in 1947. It is one of the leading telephone codes for this central business area of Chicago, including downtown and the Chicago Loop, with its vibrant music scene and great architecture.
Where is 312 Area Code Located?
The 312 area code is located in Illinois, United States. This regional code primarily serves the city of Chicago, including its downtown, the Chicago Loop, and nearby areas.
History of Area Code 312
American Telephone and Telegraph Company (AT&T) and Bell launched the 312 area code in 1947 as the main code for the Chicago metropolitan area. 312 was the first area code for the state of Illinois. It is one of the 86 original codes from 1947. Since the establishment of 312, the area code has been split into 773 in 1996, and 872 was added as an overlay in 2009. So, 312 now has a single overlay, i.e., 872. As of now, Illinois has 17 area codes. Currently, 872 serves the entire Chicago metropolitan area.
What Time Zone is the Area Code 312 In?
The 312 area code lies within the Central (America/Chicago) time zone. The time here is usually 6 hours behind Coordinated Universal Time (UTC) and Greenwich Mean Time (GMT).
Dialing Format for 312 Area Code
The dialing pattern to reach someone with a 312 regional code phone number is:
- For local calls, dial 123-XXXX, where 123 is the central office code to direct the call to the service provider, and the last four digits are the subscriber number.
- For regional calls, use 312-123-XXXX. Here, 312 is the area code of the intended region, and the last seven digits are the subscriber phone number with the exchange code and the subscriber number. ‘1’ should be added before the area code if the region still implements the 10-digit dialing.
- For international calls, dial 011-1-312-123-XXXX, where 011 is the international access code of the caller’s country. ‘1’ is the US entry country code, 312 is the area code, and the recipient’s phone number is the last seven digits.
Top County in Area Code 312
- Cook
Top 10 Cities in Area Code 312
| Chicago | Cicero |
| Schaumburg | Glenview |
| Buffalo Grove | Wheeling |
| Northbrook | Roselle |
| Brookfield | Deerfield |
ZIP Codes in Area Code 312
| ZIP Code | Location |
|---|---|
| 60601-60607, 60610-60612, 60616, 60654, 60661, 60664, 60669, 60670, 60673-60675, 60677, 60680, 60681, 60684-60686, 60689-60691, 60693-60697, 60699 | Chicago |
Nearby Area Codes
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Frequently Asked Questions
When we talk to clients about our IT services for their company, a few of the same questions come up.
Is the 312 area code a scam?
No, 312 is not a scam itself. However, the fraudsters use the 312 area code phone number to commit the fraud.
What is the zip code for the 312 area code?
Area code 312 covers the central city of Chicago, Illinois, and includes the Chicago loop extending up to the near north side. The first zip codes, 60601-60607, are assigned for the loop. 60610 and 60611 serve the Gold Coast and Streeterville.
What city has a 312 area code?
Chicago has had 312 area codes as its main area code since 1947AD.
What area code is Chicago?
The city of Chicago is served by 312 and 773.
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