<Tr> <Td> - Montford, Shrops . </Td> <Td> 43.46 m / s (1,535 cu ft / s) </Td> </Tr> <Tr> <Td_colspan="2"> Tributaries (light blue) and major settlements on and near the Severn (bold blue) </Td> </Tr> <P> The River Severn (Welsh: Afon Hafren, Latin: Sabrina) is a river in the United Kingdom . At about 220 miles (354 km), it is usually considered to be the longest in the UK . It rises at an altitude of 2,001 feet (610 m) on Plynlimon, close to the Ceredigion / Powys border near Llanidloes, in the Cambrian Mountains of mid Wales . It then flows through Shropshire, Worcestershire and Gloucestershire, with the county towns of Shrewsbury, Worcester and Gloucester on its banks . With an average discharge of 107 m / s (3,800 cu ft / s) at Apperley, Gloucestershire, the Severn is the greatest river in terms of water flow in England and Wales . </P> <P> The river is usually considered to become the Severn Estuary after the Second Severn Crossing between Severn Beach, South Gloucestershire and Sudbrook, Monmouthshire . The river then discharges into the Bristol Channel which in turn discharges into the Celtic Sea and the wider Atlantic Ocean . The Severn's drainage basin area is 4,409 square miles (11,419 km), excluding the River Wye and Bristol Avon which flow into the Severn Estuary . The major tributaries to the Severn are the Vyrnwy, Clywedog, Teme, Avon and Stour . </P>

Where is the start of the river severn