The name "London Bridge" refers to several historic crossings that have spanned the River Thames between the City of London and Southwark, in central London since Roman times. The current crossing, which opened to traffic in 1973, is a box girder bridge built from concrete and steel. It replaced a 19th-century stone-arched bridge, which in turn superseded a 600-year-old stone-built medieval structure. In addition to the roadway, for much of its history, the broad medieval bridge supported an extensive built up area of homes and businesses part of the City's Bridge ward and its southern end in Southwark was guarded by a large stone City gateway. The medieval bridge was preceded by a succession of timber bridges, the first of which was built by the Roman founders of London (Londinium) around 50 AD.

The City of London, widely referred to simply as the City, is a city, ceremonial county and local government district that contains the ancient centre, and constitutes, along with Canary Wharf, the primary central business district (CBD) of London and one of the leading financial centres of the world. It constituted most of London from its settlement by the Romans in the 1st century AD to the Middle Ages, but the modern area referred to as London has since grown far beyond the City of London boundary. The City is now only a small part of the metropolis of Greater London, though it remains a notable part of central London. The City of London is not one of the London boroughs, a status reserved for the other 32 districts. It is also a separate ceremonial county, being an enclave surrounded by Greater London, and is the smallest ceremonial county in England.