London is the capital and largest city of England, and the United Kingdom, with a population of around 8.8 million,^[1] and the largest city in Western Europe by metropolitan area, with a population of 14.8 million.^{[9][note 1]} It stands on the River Thames in south-east England at the head of a 50-mile (80 km) estuary down to the North Sea and has been a major settlement for nearly two millennia.^[10] The City of London, its ancient core and financial centre, was founded by the Romans as Londinium and retains its medieval boundaries.^{[note 2][11]} The City of Westminster, to the west of the City of London, has for centuries hosted the national government and parliament. Since the 19th century,^[12] the name "London" also refers to the metropolis around this core, historically split among the counties of Middlesex, Essex, Surrey, Kent, and Hertfordshire,^[13] which since 1965 has largely comprised Greater London,^[14] which is governed by 33 local authorities and the Greater London Authority.^{[note 3][15]}