High Quality Content by WIKIPEDIA articles! The Pensacola Dam, also known as the Grand River Dam, is a multiple-arch buttress dam on the Grand River in-between Disney and Langley in the U.S. state of Oklahoma. The dam is operated by the Grand River Dam Authority and creates Grand Lake o` the Cherokees. After decades of vision and planning, it was constructed between 1938 and 1940 for the purposes of hydroelectric power generation, flood control and recreation. It is Oklahoma`s first hydroelectric power plant and is referred to as the longest multiple-arch dam in the world.