The St. Louis District is strategically located at the crossroads of three major river systems: the Illinois, Mississippi and Missouri. The District encompasses some 28,000 square miles, almost equally divided between Illinois and Missouri. The St. Louis District is responsible for maintaining a 9-foot-deep navigation channel on 300 miles of the Mississippi, 80 miles of the Illinois and 36 miles of the Kaskaskia Rivers. District personnel operate and maintain five lock and dam sites, four on the Upper Mississippi and one on the Kaskaskia River. In addition to the rivers, the District operates and maintains five multi-purpose lakes. Their purposes include environmental stewardship, habitat restoration, fish and wildlife management, flood damage reduction, water supply, hydropower and recreation.