The London Borough of Richmond upon Thames in south-west London, England, forms part of Outer London and is the only London borough on both sides of the River Thames. It was created in 1965 when three smaller council areas amalgamated under the London Government Act 1963. Three districts of the area are within the London postal district. It is governed by Richmond upon Thames London Borough Council.
The borough is home to the National Physical Laboratory and the attractions of Hampton Court Palace, Twickenham Stadium and the WWT London Wetlands Centre that draw domestic and international tourism.
The borough was formed in 1965 by the merger of the Municipal Borough of Twickenham from Middlesex with the Municipal Borough of Richmond and the Municipal Borough of Barnes from Surrey; council offices were centred at York House in Twickenham. The name "Richmond upon Thames" was coined at that time; it is now commonly but inaccurately used to refer to Richmond only.
Three royal palaces present some of London's fine examples of Tudor architecture. tall-ceiling Georgian, Regency, Victorian and Edwardian styles were in the borough early epitomised by the wealthiest inhabitants of London whose homes largely still stand, built in what were sedate riverside villages, from Garrick Villa to Kew Green. Most instrumental to founding a new mainstream style was avant-garde 18th century neo-gothic Strawberry Hill House by Horace Walpole.