Fort Patrick Henry Dam is a hydroelectric dam on the South Fork Holston River within the city of Kingsport, in Sullivan County in the U.S. state of Tennessee. It is the lowermost of three dams on the South Fork Holston owned and operated by the Tennessee Valley Authority, which built the dam in the early 1950s to take advantage of the hydroelectric potential created by the regulation of river flow with the completion of Watauga Dam, South Holston Dam, and Boone Dam (which were primarily flood control structures) further upstream in preceding years. The dam impounds the 872-acre (353 ha) Fort Patrick Henry Lake. While originally built for hydroelectric generation, the dam now plays an important role in the regulation of water flow and water temperature for the John Sevier Fossil Plant and o