The Cumberland River is a waterway in the Southern United States
. It is 688 miles (1,107 km) long.It starts out as three separate forks that join in Harlan County, KY. Martins Fork starts in Hensley Settlement (Kentucky) on Brush Mountain in Bell County, KY and snakes its way north through the mountains to Baxter, KY.
Past Cumberland Falls, the river continues to grow in size as it merges with more creeks and streams. It is the source waters of the manmade Lake Cumberland as well as Old Hickory Lake northeast of Nashville, TN. After flowing through Nashville, the river continues west through Tennessee and back into Kentucky at the Land Between the Lakes National Recreation Area, a section of land nestled between Lake Barkley, which is fed by the Cumberland River, and Kentucky Lake.