Northumberland House in the context of "Equestrian statue of Charles I, Charing Cross"

In British usage, the term townhouse originally referred to the opulent town or city residence (in practice normally in Westminster near the seat of the monarch) of a member of the nobility or gentry, as opposed to their country seat, generally known as a country house or, colloquially, for the larger ones, stately home. The grandest of the London townhouses were stand-alone buildings, comparable to the hôtel particulier, which notably housed the French nobleman in Paris, as well as to the urban domus of the nobiles of Ancient Rome. but many were terraced buildings.

British property developers and estate agents nowadays often use the term "townhouse" for terraced buildings, following the North American usage of the term, to aggrandise modest dwellings and attract buyers who associate the term "terraced house" with the cheap terraced housing built in the Victorian era to accommodate workers. The upmarket Victorian terraced housing, which can be found around many of London's garden squares, seems to be widely forgotten in these circles.

Northumberland Avenue is a street in the City of Westminster, Central London, running from Trafalgar Square in the west to the Thames Embankment in the east. The road was built on the site of Northumberland House, the London home of the Percy family, the Dukes of Northumberland between 1874 and 1876, and on part of the parallel Northumberland Street.

When built, the street was designed for luxury accommodation, including the seven-storey Grand Hotel, the Victoria and the Metropole. The Playhouse Theatre opened in 1882 and became a significant venue in London. From the 1930s onwards, properties were used less for hotels and more for British Government departments, including the War Office and Air Ministry, later the Ministry of Defence. The street has been commemorated in the Sherlock Holmes novels including The Hound of the Baskervilles, and is a square on the British Monopoly board.

Devonshire House in Piccadilly, was the London townhouse of the Dukes of Devonshire during the 18th and 19th centuries. Following a fire in 1733 it was rebuilt by William Cavendish, 3rd Duke of Devonshire, in the Palladian style, to designs by William Kent. Completed circa 1740, it stood empty after the First World War and was demolished in 1924.

Many of Britain's great noblemen maintained large London houses that bore their names. As a ducal house (only in mainland Europe were such houses referred to as palaces), Devonshire House was one of the largest and grandest, ranking alongside Burlington House, Montague House, Lansdowne House, Londonderry House, Northumberland House, and Norfolk House. All of these have long been demolished, except Burlington and Lansdowne, both of which have been substantially altered.

Northumberland House is a 1752 landscape painting by the Italian artist Canaletto. Painted during his nine-year stay in Britain he depicts Northumberland House on the Strand by Charing Cross in London close to the location of the later Trafalgar Square. Canaletto was commissioned by the Westminster property's owner Sir Hugh Smithson, then 2nd Earl of Northumberland (later the Duke of Northumberland). Smithson was his most important patron during his time in England. The work shows Northumberland House at the middle of the eighteenth century. On the right of the painting is Hubert Le Sueur's Equestrian statue of Charles I