Carlyle Lake is the largest man-made reservoir, spanning over 26,000 acres. Created by damming the Kaskaskia River, it serves multiple purposes including flood control, recreation and providing a habitat for various wildlife species.

The lake was completed and opened to the public in 1967. It boasts an impressive array of recreational activities such as boating, fishing (known for crappie and catfish), swimming beaches along with more than nine marinas offering boat rentals.

Surrounding Carlyle Lake are extensive campgrounds and picnic areas that attract visitors year-round. The adjacent Eldon Hazlet State Recreation Area provides additional amenities like hiking trails while hosting events throughout different seasons making this destination popular among outdoor enthusiasts.

Constructed in 1967, the lake was created by damming the Kaskaskia River for flood control and water supply purposes. Before its transformation into a recreational area, the surrounding land primarily served agricultural uses with farms dotting the landscape.

Ownership of this territory has shifted over time; initially inhabited by indigenous peoples such as Mississippian cultures known for their mound-building practices. European settlers later acquired these lands through various treaties and purchases during westward expansion.

The park now encompasses historical features including multiple Native American archaeological sites that provide insight into early human settlement patterns in North America. The General Dean Suspension Bridge is another notable landmark within proximity to the park's boundaries-originally built in 1859 it stands as an engineering relic from pre-Civil War times.

Recent developments have focused on enhancing outdoor activities like fishing, boating, camping, hiking trails while conserving natural habitats around reservoir shores-a stark contrast to prior utilitarian land use centered on agriculture and resource management.