Area code 312 is assigned to Illinois. Area Code 312. Area code 312 was assigned to one of the original 86 numbering plan areas (NPAs) created in 1947 for the North American Numbering Plan. As a result of Illinois' dense population, particularly in the north, the state was split between four NPAs, given that each NPA could only accommodate approximately 500 central offices.[1]. Area code 312 originally served almost all of the Chicago metropolitan area in Illinois, except for portions of Grundy, Kane, Kankakee, McHenry, and Will counties located in the numbering plan area of the rest of northern Illinois, 815. The 1989 split was intended as a long-term solution to relieve exchanges in one of the largest toll-free calling zones in the nation. Press J to jump to the feed. Both area codes are overlaid with area code 872. In terms of ge… Area Code 312 is in Illinois and covers 18.22 square miles.

In terms of geographic area covered, 312 is one of the smallest area codes in the nation, encompassing only a few square miles. 50% Upvoted. On November 11, 1989, the suburbs were assigned area code 708 and 312 was reduced to Chicago. 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Illinois by Zip Code, Percentage of Population employed in Education & Social Services in Illinois by Zip Code, Percentage of Population employed in Arts, Recreation & Entertainment industry in Illinois by Zip Code, Percentage of Households with Income Under $10,000 in Illinois by Zip Code, Percentage of Households with Income Over $100,000 in Illinois by Zip Code, Percentage of Households with Income Over $200,000 in Illinois by Zip Code, Median Household Income in Illinois by Zip Code, Average Income per Person in Illinois by Zip Code, Percentage of Population Below Poverty Level in Illinois by Zip Code, Percentage of Families Below Poverty Level in Illinois by Zip Code, Percentage of Population Working from Home in Illinois by Zip Code, Percentage of Population Walking to Work in Illinois by Zip Code, Percentage of Population Taking Public Transit to Work in Illinois by Zip Code, Percentage of Population Driving to Work in Illinois by Zip Code, Percentage of Population Carpooling to 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management, administrative, and waste management services, Arts, entertainment, recreation, accommodation and food services, Other services (except public administration), Average household size of owner-occupied unit, Average household size of renter-occupied unit, Mortgage payment as a percentage of income. I know that the 312 area code covers only a small area of downtown Chicago. It is roughly bounded by North Avenue on the north, Western Avenue on the west, and 35th Street on the south, with Lake Michiganto the east. Area code 312 overlays the area code of 872. Postal ZIP codes beginning with 312 are located in the state of Georgia. Both area codes are overlaid with area code 872. I got my 312 phone number when I was living in 60616. save hide report. I can choose the area code to get when activating a prepaid SIM card by providing a certain zip code. Many countries use similar postal zones to make the mail delivery more efficient, although they do not have ZIP Codes exactly. [3][clarification needed], Coordinates: 41°52′48″N 87°37′54″W / 41.88°N 87.6316667°W / 41.88; -87.6316667, List of North American Numbering Plan area codes, Local calling guide: Chicago Zone 01: Calumet, IL, List of exchanges from AreaCodeDownload.com, 312 Area Code, https://en.wikipedia.org/w/index.php?title=Area_code_312&oldid=941870566, Telecommunications-related introductions in 1947, Wikipedia articles needing clarification from February 2013, Creative Commons Attribution-ShareAlike License. Area code 312 is an Illinois area code that covers Chicago and part of its surrounding area. The plan area is completely surrounded by area code 773, which serves the rest of Chicago.