331 Area Code is part of 0 counties in the state of Illinois. There are around 0 cities in the 331 area code. The 331 area code is located in the EDT timezone. Illinois has an avarage population of 12,947,252 spread between the coordinates of +40.349457 Latitude and -88.986137 Longitude.
Below you will find more info about 331 Area Code and also zip codes, counties, cities and the post offices that belong to this Area Code.