Saint Clair County, Illinois, USA
County or equivalent
Location overview
St. Clair County lies in southwestern Illinois along the Mississippi River, across from St. Louis, Missouri. Belleville is its county seat and largest city. Founded in 1790, it predates Illinois statehood and was the first county established in what is now Illinois. Its western communities form part of the urban Metro East area, while farms and smaller settlements occupy much of its eastern countryside. The county is part of the wider St. Louis metropolitan region.