The Bakerloo line is a London Underground line that runs from Harrow & Wealdstone in suburban north-west London to Elephant & Castle in south London, via the West End. Printed in brown on the Tube map, it serves 25 stations, 15 of which are underground, over 23.2 kilometres (14.4 mi). It runs partly on the surface and partly through deep-level tube tunnels.

The London Underground is a rapid transit system serving Greater London and some parts of the adjacent home counties of Buckinghamshire, Essex and Hertfordshire in England.