Hendon covers around 8,250 acres (33 km2) which included Mill Hill, as well as Golders Green and Childs Hill. In 1931 the civil parish of Edgware was abolished and its area added to the great civil parish of Hendon. It is 7 miles (11 km) northwest of Charing Cross.
Hendon is Saxon and means the "high down", and its earliest known use is in 1005 as Heandunigna. It was located in the Hundred of Gore in the county of Middlesex. Between 1835 and 1930 Hendon Union was a Poor Law Union, and Registration District. The Registration District originally stretched further into the west of Middlesex and included parishes that were transferred to Harrow and Wembley Registration Districts in 1934. These included Edgware, Great Stanmore or Stanmore, Little Stanmore, Kingsbury, Harrow-on-the-Hill, Pinner, and Willesden.
There is evidence of Roman activity in Hendon, and along its western edge runs the Roman Road Watling Street. Hendon Manor was recorded in the Domesday survey of 1087 as lands belonging to Westminster Abbey. From at least the Saxon period until the 14th century most economic activity was centred on the extensive woodlands, cultivated for firewood and pigs, and an ancient route out of London, passing through Hampstead, Golders Green, and Mill Hill, (with slight varition in its course) continued to be important until the early 19th century. During the 17th century the area became famous for its hay. In 1765 the manor came into the possession of the actor David Garrick. In 1868 a station was opened on the Midland Railway, and this encouraged some suburban development in Hendon during the 1880s and 1890s. Samuel Clarke established the Pyramid and Fairy light works in Child’s Hill during 1885, the first of Hendon’s factories, which was joined by a number of other manufactories. But it was the arrival of the trams and tubes between 1906 and 1924, that promoted the greatest growth. This was twofold as it provided not only a means of commuting for people living the area into central London, but also provided reasonable transport for workers to come into the area. By the 1930s Hendon was a recognised industrial area of London, with companies like Schweppes, Johnson’s Photographic Ltd and Handley Page, the aircraft manufacturers. However much of Hendon’s industry was minor engineer units, often employing fewer than twenty people. During the post war period demand for new housing pushed industry out of the area, and established the district as solely suburban in nature.
Hendon is famous as the location of Hendon Aerodrome which was established by Claude Grahame-White in 1911. This is in an area of Hendon now known as Colindale. Hendon Aerodrome can be credited with the first airmail delivery; the first parachute descent from a powered aircraft; and the first night flights. During World War II RAF Hendon provided the first aerial defence of a city. It is believed that the first casualty in the Battle of Britain was an RAF Hurricane pilot from Hendon. It closed to flying in 1968 and is now the site of the RAF Museum.
The Wikipedia article entitled  describes a number of areas within the former borough such as Church End, The Burroughs, Parson Street and Holders Hill, and Brent Street (all of which are redirected here with the exception of Church End which is redirected to Finchley).