St Margarets is an affluent suburb and neighbourhood in the London Borough of Richmond upon Thames, about 9 miles (14 km) west-southwest of central London. It is bounded by the Thames Tideway to the north-east, and the River Crane to the north-west and north where the land tapers between these rivers. Land and buildings closer to Richmond Bridge than the eponymous railway station are, traditionally distinctly, known as East Twickenham. Both places go by their post town and traditional parish, Twickenham quite often; in the 19th century the south of St Margarets was marked on maps as Twickenham Park.

The London Borough of Richmond upon Thames in southwest 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. It is governed by Richmond upon Thames London Borough Council and is divided into nineteen wards. The population is 198,019 and the major settlements are Barnes, East Sheen, Mortlake, Kew, Richmond, Twickenham, Teddington and Hampton.