St. Clair County is a county located in the U.S. state of Illinois, and determined by the U.S. Census Bureau to include the mean center of U.S. population in 1970. As of 2006, the population was 260,919. Its county seat is Belleville, Illinois.
It is a part of the St. Louis Metropolitan Area. St. Clair County is also the first county established in the state of Illinois. Its existence actually precedes the state of Illinois as it was established ...
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St. Clair County is a county located in the U.S. state of Illinois, and determined by the U.S. Census Bureau to include the mean center of U.S. population in 1970. As of 2006, the population was 260,919. Its county seat is Belleville, Illinois.
It is a part of the St. Louis Metropolitan Area. St. Clair County is also the first county established in the state of Illinois. Its existence actually precedes the state of Illinois as it was established in the Northwest Territory in 1790. The county was named in honor of Arthur St. Clair, Governor of the Northwest Territory, who organized the county in 1790. In its original boundaries, the county covered two-thirds of present-day Illinois.
According to the U.S. Census Bureau, the county has a total area of 674 square miles (1,746 km²), of which 664 square miles (1,719 km²) is land and 10 square miles (26 km²) (1.51%) is water.
The county forms part of the semi-rural, sparsely-populated eastern portion of the St. Louis metropolitan area ...
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