872 - Third Chicago's Area Code 
11 digits phone number

The city of Chicago, IL (USA) have  a new area code. As of November 7th, 2009, the new 872 area code is used for new phone customers in the city. Existing customers will keep their current numbers. 

Currently, the 312 area code covers downtown and the Loop. And the 773 area code was introduced in 1995 and covers the rest of Chicago and was used already in July, 2009.

With the addition of Chicago's third area code, 872, callers will have to dial 11 digits number, so please remember to dial "1"  plus  one of the city's three area codes plus the seven-digit local phone number (1 + 773 + phone number), even if calling someone within the same area code.

Information: November 1st, 2009.