Hendon was an ancient parish of around 8,250 acres (33 km2) in Middlesex, on the border with Hertfordshire. As well as Hendon itself, the parish included Childs Hill, Golders Green and Mill Hill. In 1879 the parish was made a local government district. Such districts became urban districts in 1894. In 1931 the urban district absorbed the neighbouring parish of Edgware, and the following year the urban district was incorporated to become a municipal borough. The borough was abolished in 1965 when the area was transferred from Middlesex to Greater London and became part of the London Borough of Barnet.

Hendon is an urban area in the Borough of Barnet, northwest London 7 miles (11 km) northwest of Charing Cross. Hendon was an ancient manor and parish in the county of Middlesex and a former borough, the Municipal Borough of Hendon; it has been part of Greater London since 1965. Hendon falls almost entirely within the NW4 postcode, while the West Hendon part falls in NW9. Colindale to the northwest was once considered part of Hendon but is today separated by the M1 motorway.