The Volunteer States capital is located in Nashville, and the state has a land area of 42,146 square miles. Tennessee's highest point is Clingmans Dome at 6,643 feet and its lowest point is on the Mississippi River at 178 feet. Although Tennessee joined the Confederacy during the Civil War, there was much pro-Union sentiment in the state, which was the scene of extensive military action. With six other states, Tennessee shares the extensive federal reservoir developments on the Tennessee and Cumberland River systems. The Tennessee Valley Authority operates a number of dams and reservoirs in the state. Among the major points of interest are the Andrew Johnson National Historic Site at Greeneville, the American Museum of Atomic Energy at Oak Ridge, Great Smoky Mountains National Park, the Hermitage (home of Andrew Jackson near Nashville), Rock City Gardens near Chattanooga, and three National Military Parks. The name of the state is taken from the Tennessee R., the name of which is derived from that of a Cherokee Indian village. Tennessee is called the Volunteer State.