Flannagan Reservoir is a 1,143-acre impoundment located in Dickenson County. The reservoir was built to provide flood control, pollution abatement, fish and wildlife habitat, and recreational opportunities. The U.S. Army Corps of Engineers completed construction of the dam and project in 1964. Fifty miles of beautiful shoreline consisting of mature hardwood forest interspersed with spectacular rock bluffs surround this deep, clear reservoir. At full pool elevation of 1396 feet above sea level, the lake has a maximum depth of 166 feet and an average depth of 58 feet. During the summer and fall the lake is incredibly clear, with visibility often exceeding 20 feet.