Area code 618
Area code 618 is an area code for Illinois. It was one of the first area codes created in 1947. It covers the entire southern portion of Illinois, consisting of cities such as Belleville, Fairview Heights, Carbondale, Cairo, Edwardsville, Collinsville, and Granite City. It will be overlaid by 730 in July 7, 2023, making it the last area code of Illinois to have an overlay.