This is actually on the Kentucky side of the border in Big South Fork, but for continuity I will put it with TN.
This wall is about a 1/2 mile hike from the outdoor coal mine museum, up the Blue Heron Trail just past Crack in the Rocks - but BEFORE you get to the looong staircase. Just before the staircase you will see a big overhanging face with some hard bolted lines there and just around the corner are some nice below vertical lines bolted up the water marks. Probably about 60-80 feet.
Estimate some of these lines start around 5.7-5.8