Area codes are how the North American Numbering Plan (NANP) sorts phone numbers by geographic region. So, if you’re calling from outside a specific region, you need the right area code to connect.
The 842 area code belongs to Chicago, Illinois. It’s what’s known as an “overlay” area code, which we’ll explain later in this article.
Read on to learn about the history of the 842 area code, where it’s located, and how it’s used.
Where is area code 872?
The 872 area code is located in the Central Time Zone (America/Chicago time zone) and primarily serves the city of Chicago, Illinois. In fact, about 97% of the area code’s population lives in Chicago.
Area code 872 overlays both the 312 and 773 area codes, meaning that the same geographic areas are covered by all three area codes.
History and Purpose of the 872 Area Code
Area codes can only accommodate so many phone numbers. When an area code is running out of available numbers, regulators may introduce what’s known as an overlay area code to relieve the pressure. That’s how the 872 area code came into being.
Chicago’s original area code, 312, was running out of available phone numbers, so the 872 area code was introduced as an overlay to allow for more phone numbers to be assigned in the same geographic area.
The 872 area code officially came into service on November 7, 2009. At the time, it was the 343rd area code in service across the country and the 13th in the state of Illinois.
Overlay area codes and nearby area codes
The 872 area code is an overlay for area codes 312 and 773. In practical terms, that means the same geographic area is served by all three area codes. The overlay was implemented to make sure there were enough phone numbers to serve the area.
Here are some of the area codes that border the 847 area code in Illinois:
- 630
- 708
- 847
Prefix Usage and Telephone Carriers
The prefixes within the 872 area code are divided among landline and wireless carriers.
Currently, about 31% of the prefixes are assigned to landlines, while roughly 62% are assigned to wireless carriers. The remaining 6% are listed as “unknown.”
Many different telephone carriers use prefixes within the 872 area code, including both landline and wireless providers.
Detailed information is available about the prefixes, the primary city each prefix serves, the carrier to whom it’s assigned, and the date the prefix was first put into service.
Mnemonics and other interesting facts
Area codes don’t typically spell out words like phone numbers used to do, but you can still sometimes use the numbers on a keypad to create mnemonics. For example, the 8, 7, and 2 in the 872 area code could stand for TPA or TPB, among other things.
Also, while the 872 area code covers a wide area, the majority of its population (around 14%) lives in Cook County, Illinois.
Closing Thoughts
The 872 area code covers Chicago, Illinois, and overlays the 312 and 773 area codes. When you dial a Chicago number, you’ll need to include the area code, even if you’re calling from within the city.
Area codes are an essential part of today’s telecommunications system, allowing us to connect with each other across vast distances.