The River Wissey is a river in Norfolk, eastern England. It rises near Bradenham, and flows for nearly 31 miles (50 km) to join the River Great Ouse at Fordham. The lower 11.2 miles (18.0 km) are navigable. The upper reaches are notable for a number of buildings of historic interest, which are close to the banks. The river passes through the parkland of the Arts and Crafts Pickenham Hall, and further downstream, flows through the Army's Stanford Training Area, which was created in 1942 by evacuating six villages. The water provided power for at least two mills, at Hilborough and Northwold. At Whittington, the river becomes navigable, and is surrounded by fenland.