Turnham Green tube station in the context of Cross-platform interchange

The District line is a London Underground line running from Upminster in the east and Edgware Road in northwestern Central London to Earl's Court in west London, where it splits into multiple branches. One branch runs to Wimbledon in south-west London and a short branch, with a limited service, only runs for one stop to Kensington (Olympia). The main route continues west from Earl's Court to Turnham Green after which it divides again into two western branches, to Richmond and Ealing Broadway.

Printed in green on the Tube map, the line serves 60 stations (more than any other Underground line) over 40 miles (64 km). It is the only Underground line to use a bridge to traverse the River Thames, crossing on both the Wimbledon and Richmond branches. The track and stations between Barking and Aldgate East are shared with the Hammersmith & City line, and between Tower Hill and Gloucester Road and on the Edgware Road branch they are shared with the Circle line. Some of the stations between South Kensington and Ealing Common are shared with the Piccadilly line. Unlike London's deep-level lines, the railway tunnels are just below the surface, and the trains are of a similar size to those on British main lines.

Chiswick (/ˈtʃɪzɪk/ CHIZ-ik) is a district in West London, split between the London Boroughs of Hounslow and Ealing. It contains Hogarth's House, the former residence of the 18th-century English artist William Hogarth, Chiswick House, a neo-Palladian villa regarded as one of the finest in England and Fuller's Brewery, London's largest and oldest brewery. In a meander of the River Thames used for competitive and recreational rowing, with several rowing clubs on the river bank, the finishing post for the Boat Race is just downstream of Chiswick Bridge.

Old Chiswick was an ancient parish in the county of Middlesex, with an agrarian and fishing economy beside the river; from the Early Modern period, the wealthy built imposing riverside houses on Chiswick Mall. Having good communications with London, Chiswick became a popular country retreat and part of the suburban growth of London in the late 19th and early 20th centuries. It was made the Municipal Borough of Brentford and Chiswick in 1932 and part of Greater London in 1965, when it merged into the London Borough of Hounslow. Modern Chiswick is an affluent area which includes the early garden suburb Bedford Park, Grove Park, the Glebe Estate, Strand-on-the-Green and tube stations Chiswick Park, Turnham Green, and Stamford Brook, as well as the Gunnersbury Triangle local nature reserve. Some parts of Bedford Park and Acton Green are in the Chiswick W4 postcode area but the London Borough of Ealing. The main shopping and dining centre is Chiswick High Road.