Appalachian Power Company built Smith Mountain and Leesville Dams between 1960 and 1963 to generate hydroelectric energy. West of Smith Mountain Dam, the waters of the Roanoke and Blackwater Rivers formed Smith Mountain Lake, covering 20,600 acres that had primarily been farmland. On 7 March 1966, the lake first reached full pond at 795 feet above sea level. Forty miles long, the lake features 500 miles of shoreline, of which 275 miles lie in Franklin County. Smith Mountain Lake became a popular recreational destination and gave rise to a thriving residential community. It is the largest lake wholly within Virginia.