The River Thames flows through southern England. It is the longest river entirely in England and the second longest river in the United Kingdom. While it is best known because its lower reaches flow through central London, the river flows alongside several other towns and cities, including Oxford, Reading, Henley-on-Thames, Windsor, Kingston upon Thames and Richmond. The river gives its name to several geographical and political entities including the Thames Valley, a region of England centred around the river between Oxford and west London, the Thames Gateway, the area centred around the tidal Thames, and the Thames Estuary to the east of London.
