Belleville (
French:
Belle ville, meaning "Beautiful city") is a city in
St. Clair County,
Illinois,
United States, co-extensive with
Belleville Township. As estimated by the US Census Bureau in 2012, shown on the city's economic development page, the city has a population of 43,765. It is the eighth-most populated city outside the
Chicago Metropolitan Area and the most populated city south of
Springfield in the state of Illinois. It is the
county seat of St. Clair County, and the seat of the
Roman Catholic Diocese of Belleville and the
National Shrine of Our Lady of the Snows. Belleville is the most populated city in the
Metro-East region of the
St. Louis Metropolitan Area and in
Southern Illinois. Due to its proximity to
Scott Air Force Base, the population receives a boost from military and federal civilian personnel, defense contractors, and military retirees.