Area Code: 331

331 Area Code belongs to the state of Illinois. The following cities fall under this area code: Addison, Aurora, Bartlett, Batavia, Bensenville, Bloomingdale, Bolingbrook, Carol Stream, Darien, Downers Grove, Elmhurst, Glen Ellyn, Glendale Heights, Hanover Park, Lisle, Lombard, Naperville, Roselle, St. Charles, Streamwood, Villa Park, West Chicago, Westmont, Wheaton, Woodridge. There have been a total of 4638 Numbers for this area code.