In Kentucky Dam's Mammoth Lock on the Lower Tennessee River.The river packet Gordon C. Greene is shown in the lock at Kentucky Dam during the Annual TV Ho! Cruise promoting "The Great Lakes of the South". The Cruise starts from Paducah, Kentucky, in June of each year and ends 650 miles upstream at knoxville. Tennessee. The Lock at Kentucky Dam is the highest single lift lock in the world with a normal lift of 55 feet. It is 100 feet wide by 600 feet long.