Area code 773

Area code 773 serves Chicago, Illinois, outside the Chicago Loop and the innermost neighborhoods.

At first, 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 spread of cell phones and pagers made it obvious 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. Tolerant dialing of 312 continued across Chicago until January 11, 1997.  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.

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