Lake Wappapello is a reservoir on the St. Francis River, formed by Wappapello Dam. Created in 1941, this 45,000-acre lake is located 120 miles south of St. Louis, Missouri. Its primary purpose is flood control though it has evolved into a recreational area with ample opportunities to boat, fish, swim or camp. The reservoir lies overwhelmingly in Wayne County, but its southernmost reaches (near the dam) extend into northern Butler County. Lake Wappapello State Park lies on the southwestern side of the lake.