 Boone Dam is located above the South Fork Holston River's confluence with the North Fork Holston River (which forms the Holston River proper).The Watauga River joins the South Fork Holston almost immediately upstream from the dam, creating a V-shaped reservoir that extends for up the South Fork Holston (all the way to Bluff City) and for up the Watauga.The Sullivan-Washington county line follows the reservoir for most of its Watauga span.