The Severn River
Severn River, the longest river in Great Britain. From its source in west-central Wales, the river follows a roughly semicircular course, mostly in England, for 220 miles (355 km) to the Bristol Channel. Its mouth is a broad estuary, with tides reaching nearly to Gloucester. Tributaries include two Avon rivers and the Usk, Wye, and Teme rivers. The Severn is navigable by small barge for much of its length. Small ships travel as far as Gloucester by means of the Gloucester and Sharpness Canal. Other canals link the Severn with other parts of England. The Severn estuary is crossed by a railway tunnel and two long bridges.