Old Johnsonville was named for Andrew Johnson, military governor of Tennessee from 1862 to 1865. Although the community had been a steamboat landing prior to the Civil War, it did not gain prominence as a major supply depot until the Union Army completed the Nashville and Northwestern Railroad in May 1864. Confederate General Nathan B. Forrest destroyed the supply depot on November 4, 1864, and also destroyed the supply base and defending gunboat flotilla, while two Union redoubts built near the town for defense of the depot still remain. The guns in the earthworks were inadequate. After the war, Johnsonville thrived for forty years as a river-rail transfer point, but severe flooding stopped its growth. T.V.A. then purchased the land for Kentucky Lake, and in 1945 the town ceased to exist.