London Overground (also known simply as the Overground) is a suburban rail network serving London and its environs. Established in 2007 to take over Silverlink Metro routes, it now serves a large part of Greater London as well as the home county of Hertfordshire, with 112 stations on nine different routes.
The Overground forms part of the United Kingdom's National Rail network but it is under the concession control and branding of Transport for London. Operation has been contracted to Arriva Rail London since 2016. TfL assigned orange as a mode-specific colour for the Overground in branding and publicity including the roundel, on the Tube map, trains and stations.