The River Severn (Welsh: Afon Hafren, Latin: Sabrina) is the longest river in Great Britain, at 220 miles (354 km). It rises at an altitue of 2,001 feet (610 m) on Plynlimon near Llanidloes, Powys, 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 m³/s at Apperley, Gloucestershire, the Severn is England's greatest river in terms of water flow, and is considered one of the ten major rivers of the United Kingdom.