The Severn Tunnel between New Passage and Portskewett carries the railway under the estuary and forms the most direct railway route between the south of England and South Wales. The tunnel was completed in 1886 at a cost of £2 million after many difficulties from flooding. It is the longest railway tunnel in Britain, being four miles in length, of which 2 1/4 miles are under the river.
The most original southerly bridge is the Severn, which forms part of the London-South Wales Motorway (M4). It crosses the Severn Estuary between Aust, near Bristol and Beachley, Monmouthshire. Work was completed on the £8 million bridge in 1966.
Thomas Telford built several road ridges over the river, including Montford and Buildwas in Shropshire, Bewdley in Worcestershire, Mythe at Tewkesbury and Over at Gloucester.
The structure at Ironridge was the first large bridge to be made of cast iron. It was erected in 1780 and still stands, crossing the river in a single span of 120 feet. At Coalbrookdale, near Ironbridge, the first barge made of iron was launched successfully on the Severn in 1787 by John Wilkinson.
The second Severn Crossing Bridge opened on the 5th June 1996, after a three and half year construction, which carries 4 lanes over the River Severn and River Wye. Total length 5,128 meters, with a cost of £330 million. The bridge was renamed the Prince of Wales in July 2018.