River Thames

The River Thames is, at 215 miles (346 km) from source to sea, the longest river that runs wholly in England (the Severn, which rises in Wales, is longer). It rises near Lechlade in Gloucestershire and runs through Oxford, Reading, Wimdsor and London before entering the North Sea. The river is tidal as far as Teddington Lock, in west London. A number of canals were built in the 18th and 19th centuries connecting the Thames to the inland waterways system; most notable are the Kennett & Avon Canal, connecting the Thames to Bristol and the west coast, and the Grand Junction Canal (since 1929 the Grand Union Canal) which runs from London to Northamptonshire and links London to the canal system of the Midlands and northern England.