Watts Bar Lake 24″x36″ One-sided. Scale 1:48,000 Waterproof and Tear Resistant! Watts Bar Lake is on the Tennessee River and is surrounded by Loudon, Roane, Rhea, and Meigs Counties in Tennessee. Watts Bar Lake covers 39,000 acres at full pool, and has 771 miles of shoreline. The lake extends 72.4 miles from the Watts Bar Dam up to Ft. Loudon dam, with the maximum depth being approximately 70 feet near the dam. The principal tributaries of Watts Bar are the Clinch River and the Tennessee River. Watts Bar Lake is one of south’s largest lakes. The watershed (the land the water drains from) for the lake is 17,310 square miles.