What is 332 area code?

The 332 area code is an overlay area code for the Chicago, Illinois area. It was introduced to alleviate the dwindling supply of phone numbers in the existing 312 and 773 area codes. This means that in the city of Chicago and some surrounding areas, you might have phone numbers with either the 312, 773, or 332 area codes. It began service in 2009. Because it's an overlay, it didn't require existing customers to change their numbers.