The John Rankin Lock (formerly named Lock D) is part of the Tennessee-Tombigbee Waterway. It is located in Itawamba County, Mississippi, approximately 6 miles (9.7 km) north of Fulton. It is named for John E. Rankin, Mississippi's First District Representative in the United States House of Representatives.
The Tennessee-Tombigbee Waterway (popularly known as the Tenn-Tom) is a 234 mile (377 km) artificial waterway that provides a connecting link between the Tennessee and Tombigbee rivers. The waterway begins at Pickwick Lake on the Tennessee River, then flows southward through northeast Mississippi and west Alabama, finally connecting with the established Warrior-Tombigbee navigation system at Demopolis, Alabama.
After 12 years of construction, the waterway and its seventeen public ports and terminals opened to commercial traffic in January 1985. In addition to the original 110,000 acres (445 km²) of land acquired for the construction and operation of the project, another 88,000 acres (356 km²) have been purchased and managed by the two state conservation agencies for wildlife habitat preservation and mixed use including hunting and parks.
The elevation change between the two ends of the waterway is 341 feet (104 m).