Area code 773 serves Chicago, Illinois, outside the Loop and the innermost neighborhoods.
Originally, all of Chicago and its suburbs used area code 312. In 1989, area code 708 was created for the suburbs, leaving the city in area code 312.
By the mid-1990s, Chicago's continued growth and the proliferation of cell phones and pagers made it apparent that the city needed a new area code. It was decided to split off all of the city outside the downtown area as 773. The new area code went into effect on October 12, 1996. Permissive dialing of 312 continued across Chicago until January 11, 1997.[1][2] On August 10, 2007, the Illinois Commerce Commission announced that area code 872 would overlay area codes 312 and 773; it went into service on November 7, 2009.
The Illinois side of the Chicago area–312/773/872, 708, 847/224, 630/331 and portions of 815/779–is one of the largest local calling areas in the United States; with few exceptions, no long-distance charges are applied from one portion of the metro area to another.[3]
^"AT&T Area Code History: Illinois". AT&T. 2009. Archived from the original on October 28, 2007. Retrieved August 19, 2009.
^"Grace Period Ends for 773 Area Code". Chicago Tribune. January 11, 1997. Retrieved October 24, 2020.
^Local calling guide: Chicago Zone 01: Calumet, IL
Areacode773 serves Chicago, Illinois, outside the Loop and the innermost neighborhoods. Originally, all of Chicago and its suburbs used areacode 312...
numbering plan area is completely surrounded by areacode773, which serves the rest of Chicago. Both areacodes form an overlay complex with areacode 872. 312...
Illinois. It is an overlay code for a numbering plan area that comprises those of areacodes 312 and 773. The overlay commenced service on November 7, 2009...
and Orland Park. 773: Chicago, covers most of the geographical area of Chicago except the downtown Chicago Loop, which is in areacode 312. 815/779: Northern...
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geographic numbering plan areas (NPAs). Each NPA is identified by one or more numbering plan areacodes (NPA codes, or areacodes), consisting of three digits...
was divided into four numbering plan areas (217, 312, 618, and 815). The Illinois side of the Chicago area–312/773/872, 708/464, 847/224, 630/331, and...
2007, areacode 331 began overlaying areacode 630, making ten-digit dialing mandatory in the area. The Illinois side of the Chicago area–312/773/872,...
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