Cranham is a residential area of east London, and part of the London Borough of Havering. It is located 17.5 miles (28 km) east-northeast of Charing Cross and comprises an extensive built-up area to the north and a low density conservation area to the south surrounded by open land. It was historically a rural village in the county of Essex and formed an ancient parish. It is peripheral to London, forming the eastern edge of the urban sprawl. The economic history of Cranham is characterised by a shift from agriculture to housing development. As part of the suburban growth of London in the 20th century, Cranham significantly increased in population, becoming part of Hornchurch Urban District in 1934 and has formed part of Greater London since 1965. The 2011 Census population of Cranham was included in Upminster.

Hornchurch was a local government district in southwest Essex from 1926 to 1965, formed as an urban district for the civil parish of Hornchurch. It was greatly expanded in 1934 with the addition of Cranham, Great Warley, Rainham, Upminster and Wennington; and in 1936 by gaining North Ockendon. Hornchurch Urban District Council was based at Langtons House in Hornchurch from 1929. The district formed a suburb of London and with a population peaking at 131,014 in 1961, it was one of the largest districts of its type in England. It now forms the greater part of the London Borough of Havering in Greater London.