Roanoke, river, c.410 mi (660 km) long, rising in SW Va. and flowing generally southeast across the Blue Ridge Mts. and into Albemarle Sound, NE N.C. The lower river is navigable for small craft. A comprehensive flood-control and hydroelectric-power scheme has been initiated on the river. Among a series of constructed dams, John H. Kerr Dam impounds one of the largest reservoirs in the United States. Roanoke, Va., is the chief city on the river.