312 Area Code – (Location, Timezone) Read All Details Here!

Area Code 312

The 312 area code is one of the originally established telephone area codes, serves the state of Illinois (IL) and downtown Chicago. It includes the Chicago loop and its neighboring areas.


312 is a smallest territory area code, covering about few square miles. It serves Chicago, Hinsdale, La Grange Park, Northbrook, Roselle, Wheeling etc. It is surrounded by North Avenue towards north, Western Avenue towards west, 35th Street towards south and Lake Michigan towards the east.

Time Zone

Area code 312 lies in the central time zone.

History of Area Code 312

312 area code was originated in 1947, when the numbering system was established. It is one of the original 86 area codes. Due to increase in demand of telephonic codes in United States the whole United States was divided into small numbering plan areas according to North America Numbering Plan. Originally it served the Chicago metropolitan area in Illinois. 

  • On November 11, 1989, the surrounding areas of Illinois were given area code 708  so that 312 was reduced to serve Chicago.
  • In 1996, Population of Illinois was increased thereby creating the need of establishing new area codes and updated some of the phone numbers to area code 773 by splitting area code 312.
  • Due to continuous progress in digital world during 1990s as use of cell phones, monitors and fax machines increased, the area code exhausted once again and need to split again to cover the area needs.
  • So, the area code 708 was split in 1996. The area code 708 was retained to serve the southern parts. The new area codes 847 and 630 appeared in that area because of 708 split to cover the northern and the western parts, respectively.
  • On the other side, on October 11, 1996, Downtown’s surrounding area was split off as area code 773 . As a result, Chicago became one of the few cities in the nation to be split between multiple area codes, along with New York City and Los Angeles.
  • On November 7, 2009, a new area code 872 appeared as an overlay of both 312 and 773.
  • As a result of this overlay of 312/773/872, the procedure of local calls in Chicago has been changed. The new calling procedure was 10-digit dialing, in addition to the prefix ‘1’.

What is Ten-digit dialing ?

It is a telephone dialing procedure that includes the area code+ telephone number to make a call inside or outside the local area. Sometimes, the ten-digit numbers prefixed with number 1 (trunk code). This is common in areas where overlays are implemented. 10- digit dialing format, when necessary, looks like this 1+ area code+ telephone number. This is also called national format.

Is the Area code number 312 Popular in culture?

  • 312 urban wheat Densely populated with flavor and refreshment that never be forgotten.
  • The song area 312 was released in 1982 by Rez Band.
  • A restaurant named “312 Chicago” at the Kimpton Hotels. 
  • In the scene of film RoboCop 2 , the telephone number was written on empty building (312) 555-7890.
  • 312 was used as track title for the music project Radio Flyer.
  • 312 was mentioned in the Ludacris song “Area Codes” in which 43 area codes were mentioned.
  • “Girl if you ever in the 312, holla at a playa” is the lyrics of the Snoop Dogg song “That’s That”.
  • The Kanye West song “New God Flow,” also contains the number 312 in its lyrics.
  • “CECE” and “Rocky” are the characters of The Disney Channel show Shake It Up. It mentions 312 as both Rocky and Cece’s area code.
  • The jingle “3-1-2. 3-1-2 That toddlin town, that toddlin town” was used in 1960s AT&T commercial promoted calling long distance.
  • The THOTCON Chicago hacking conference was held in 2009. The name THOTCON was derived from the area code 312. TH from “three”, the O from “one”, and the T from “two”.

For More You May Also Read: 512 Area Code

Leave a Comment