St. Margarets is a suburb in the London Borough of Richmond upon Thames, England, about 9 miles (14 km) west-southwest of central London. Until 1965 it was part of Twickenham Urban District and Municipal Borough in Middlesex.
It is bounded by the River Thames to the east and the River Crane to the west and north. The northern limit, less well defined, has changed with local government boundary revisions. St Margarets does not pass any further south than Richmond Road, Twickenham. The area closer to Richmond Bridge is known as East Twickenham and is not regarded as part of St Margarets.
St Margarets takes its name from the former St Margaret's House--it was not the name of a Church of England parish. The house was the country house of Lord Cassilis, Marquis of Ailsa, and later belonged to the Earl of Kilmorey. Their names can be found in local street names, including Kilmorey Gardens and Ailsa Road.
For more information, see the EN Wikipedia article St Margarets.