River Severn

River Severn Welsh: Afon Hafren
The river seen from Shrewsbury Castle
Tributaries (light blue) and major settlements on and near the Severn (bold blue)
Location
Country	England and Wales
Region	Mid Wales, West Midlands, South West
Counties	Powys, Shropshire, Worcestershire, Gloucestershire
Cities	Shrewsbury, Worcester, Gloucester, Bristol
Physical characteristics
Source
• location	Plynlimon, Powys, Wales
• coordinates	52°29′36″N 3°44′05″W / 52.493464°N 3.734597°W / 52.493464; -3.734597
• elevation	610 m (2,000 ft)
Mouth	Severn Estuary
• location	Bristol Channel, United Kingdom
• elevation	0 m (0 ft)
Length	354 km (220 mi)
Basin size	11,420 km2 (4,410 sq mi)
Discharge
• location	Bewdley, Worcs. SO 7815 7622[1]
• average	61.17 m3/s (2,160 cu ft/s)[1]
• maximum	533.48 m3/s (18,840 cu ft/s)max recorded on 1947-03-21[2]
Discharge
• location	Apperley, Glos.
• average	107 m3/s (3,800 cu ft/s)
Discharge
• location	Montford, Shrops.[3]
• average	43.46 m3/s (1,535 cu ft/s)
Basin features
Tributaries
• left	Vyrnwy, Tern, Stour, Warwickshire Avon, Bristol Avon
• right	Teme, Leadon, Wye

The River Severn (Welsh: Afon Hafren, pronounced [ˈavɔn ˈhavrɛn]), at 220 miles (354 km) long, is the longest river in Great Britain.^[4][5] It is also the river with the most voluminous flow of water by far in all of England and Wales, with an average flow rate of 107 m³/s (3,800 cu ft/s) at Apperley, Gloucestershire. It rises in the Cambrian Mountains in mid Wales, at an altitude of 2,001 feet (610 m), on the Plynlimon massif, which lies close to the Ceredigion/Powys border near Llanidloes. The river then flows through Shropshire, Worcestershire and Gloucestershire. The county towns of Shrewsbury, Worcester and Gloucester lie on its course.

The Severn's major tributaries are the Vyrnwy, the Tern, the Teme, the Warwickshire Avon, and the Worcestershire Stour.

By convention, the River Severn is usually considered to end, and the Severn Estuary to begin, after the Second Severn Crossing, between Severn Beach in South Gloucestershire and Sudbrook, Monmouthshire. The total area of the Estuary's drainage basin is 4,409 square miles (11,419 km²). That figure excludes the area of the River Wye and the Bristol Avon, both of which flow into the Severn Estuary. The Estuary discharges into the Bristol Channel, which opens into the Celtic Sea and from there into the Atlantic Ocean.