Chicago’s south and near west suburbs are getting an additional area code following high demand for new phone numbers in the area.
The 464 area code will be issued starting Friday in the 708 area code region, which serves western and southern Cook County and eastern and southern Will County.
The new prefix will be given to new phone users and users changing their number, the Illinois Commerce Commission said Monday. Current users of the 708 area code are not affected.
The additional area code will also not affect how phone users dial. Users in the 708 region already use a 10-digit format including a +1 and the area code.
Customers can still dial just three digits to reach 911 and other municipal service numbers like 311.
The Illinois Commerce Commission first announced the impending addition of the new 464 area code in August. The commission actually approved 464 as an overlay for the 708 area code back in 1999 but did not implement it until needed.
The 708 area code was introduced to the suburbs in 1989 after Illinois Bell exhausted the use of 312 numbers in those areas. After that, the 312 area code was limited to Chicago until it was split even further and the 773 area code was added to the city in 1996.
Area codes are assigned under the North American Numbering Plan, which was implemented in 1951. The plan, which serves 20 North American countries, including the United States and Mexico, was created to make it easier to dial long-distance calls.

A map of Illinois telephone area codes, including the newest code, 464, which will be added to the existing 708 area.
North American Numbering Plan Administrator