Kansas is a relatively flat and dry state. Natural lakes in Kansas are therefore rare and small. Lake Inman in McPherson County is the largest natural lake in Kansas, with a surface area of about 160 acres, or one-fourth of a square mile.
Beginning in the 1940s, the US federal government began taking an interest in building reservoirs to mitigate the floods and droughts that are frequent in the Midwest and West.
Construction on the first US Army Corps of Engineers reservoir in Kansas began in 1940 with Kanopolis Lake, with the most recent one, Hillsdale Lake, completed in 1982. A total of 24 federally-funded reservoirs currently exist in Kansas. Geographically, they are divided between the Missouri River Basin in northern Kansas, and the Arkansas River Basin in southern Kansas.
Federal reservoirs in eastern Kansas were built and are run by the US Army Corps of Engineers, and they are intended largely for flood control. They are divided between two US Army Corps of Engineers districts, the Kansas City District in northern Kansas, and the Tulsa District in southern Kansas.
Federal reservoirs in western Kansas were built and are run by the US Bureau of Reclamation, and are intended largely for water conservation.
Many of the federally-built Kansas reservoirs host Kansas State Parks, which are operated by the Kansas Department of Wildlife, Parks, and Tourism.