Keystone Lake is a reservoir in northeastern Oklahoma on the Arkansas and Cimarron rivers. It is located upstream about from Tulsa. It was created in 1968 when the Keystone Dam was completed. The primary purposes are: flood control, hydroelectric power generation, wildlife management and recreation. General description Keystone Lake is about in area, and was designed to contain of water. It was named for the community of Keystone, which existed on the site from 1900 until 1962, when it was inundated by the waters of the lake. Construction of the lake forced the relocation of three other towns: Mannford, Oklahoma (also known as New Mannford by locals), Prue (also known as New Prue), and Appalachia Bay, Oklahoma. The town of Osage was partially abandoned to the lake, while the rest clings to the south shore. Engineers built a levee around low-lying areas of the south and east sides of Cleveland, Oklahoma to prevent flooding of that city. The shoreline extends for . Two Oklahoma state parks, Keystone State Park and Walnut Creek State Park, are located along the shores of the lake offering camping, hiking and biking trails, fishing, swimming and boating opportunities. The area also features a Yogi Bear's Jellystone Park Camp-Resort as you cross the Keystone Dam near Sand Springs. The Keystone Lake project was authorized by the Flood Control Act of 1950. It was designed and built by the Tulsa District, Army Corps of Engineers. Construction began in January 1957 and was complete for flood control purposes in September 1964. Commercial operation of the power generating facility began in May 1968. A reregulating dam, located downstream of the main dam, was also completed in 1968. Cost of the total project was approximately $123 million. In 1986, the reregulating dam was removed due to public safety issues, as 16 people had drowned at the dam. Dam construction details The dam was actually constructed across the Arkansas River, downstream of the confluence with the Cimarron River. It is built of rolled earthfill material. Maximum height of the dam is above the stream bed. The total length of the dam is , including a -long concrete section. The spillway in the concrete section is wide. The non-overflow part of the concrete section includes a power intake structure. State Highway 151 crosses the dam, connecting State Highway 51 on the south with U.S. Highway 64 on the north. The spillway is