King's Cross is a district in the London Boroughs of Camden and Islington, on either side of Euston Road in north London, England, 1.5 miles (2.4 km) north of Charing Cross, bordered by Barnsbury to the north, Clerkenwell to the southeast, Angel to the east, Holborn and Bloomsbury to the south, Euston to the west and Camden Town to the northwest. It is served by two major rail termini, St Pancras and King's Cross. King's Cross station is the terminus of one of the major rail routes between London and the North.

The area, which was historically the south-eastern part of the parish and borough of St Pancras, and once known for drug-dealing and prostitution, has undergone significant regeneration since the mid-1990s. The introduction of the Eurostar rail service at St Pancras International and the rebuilding of King's Cross station helped stimulate the redevelopment of the long-derelict railway lands to the north of the termini.

The area, historically the south-eastern part of the ancient parish and subsequent Metropolitan Borough of St Pancras, was previously known as Battle Bridge or Battlebridge after an ancient crossing of the River Fleet. The original name of the bridge was Broad Ford Bridge. The original parish church, St Pancras Old Church, located behind the stations, was built on a knoll on the west bank of the Fleet, and is believed to be one of the oldest Christian sites in Britain.

The corruption "Battle Bridge" led to a tradition that this was the site of a major battle in AD 60 or 61 between the Romans and the Iceni tribe led by Boudica (also known as Boadicea). The tradition claims support from the writing of Publius Cornelius Tacitus, an ancient Roman historian, who described the place of action between the Romans and Boudica (Annals 14.31), but without specifying where it was; Thornbury addresses the pros and cons of the identification. Lewis Spence's 1937 book Boadicea – warrior queen of the Britons includes a map showing the supposed positions of the opposing armies. The suggestion that Boudica is buried beneath platform 9 or 10 at King's Cross station seems to have arisen as urban folklore since the end of World War II. The area had been settled in Roman times, and a camp here known as The Brill was erroneously attributed to Julius Caesar, who never visited Londinium. There is still a small area named "Battle Bridge Place" between King's Cross and St Pancras stations, and "Brill Place", a road leading towards Euston from St Pancras station. An art installation named the Identified Flying Object (IFO) stands in Battle Bridge Place, part of the RELAY King's Cross Arts programme.

The Rocque map of 1746 shows the area as entirely undeveloped; however, the opening of the new Euston Road (originally New Road) in 1756 opened the area up for development. The current name has its origin in a monument to King George IV which stood from 1830 to 1845 at "the king's crossroads" where New Road (later Euston Road), Gray's Inn Road, and Pentonville Road met. The monument was sixty feet (18 m) high and topped by an eleven-foot-high (3.4 m) statue of the king; it was described by Walter Thornbury as "a ridiculous octagonal structure crowned by an absurd statue". The statue itself, which cost no more than £25, was constructed of bricks and mortar, and finished in a manner that gave it the appearance of stone "at least to the eyes of common spectators". The architect was Stephen Geary, who exhibited a model of "the Kings Cross" at the Royal Academy in 1830. The upper storey was used as a camera obscura while the base housed first a police station, and later a public house. The unpopular building was demolished in 1845, though the area kept the name of King's Cross. A structure in the form of a lighthouse was built on top of a building almost on the site about 30 years later. Known locally as the "Lighthouse Building", the structure was popularly thought to be an advertisement for Netten's Oyster Bar on the ground floor, but this seems not to be true. It is a grade II listed building.

King's Cross station now stands by the junction where the monument stood and took its name. The station, designed by architect Lewis Cubitt and opened in 1852, succeeded a temporary earlier station, erected north of the canal in time for the Great Exhibition of 1851.

St Pancras railway station, built by the Midland Railway, lies immediately to the west. They both had extensive land ("the railway lands") to house their associated facilities for handling general goods and specialist commodities such as fish, coal, potatoes and grain. The passenger stations on Euston Road far outweighed in public attention the economically more important goods traffic to the north. King's Cross and St Pancras stations, and indeed all London railway stations, made an important contribution to the capital's economy.

After World War II the area declined from being a poor but busy industrial and distribution services district to a partially abandoned post-industrial district. By the 1980s it was notorious for prostitution and drug abuse. This reputation impeded attempts to revive the area, utilising the large amount of land available following the decline of the railway goods yard to the north of the station and the many other vacant premises in the area. The King's Cross fire in 1987 in which 31 people died as a result of poor maintenance and safety procedures in the district's major Tube station only typified the level of dilapidation and neglect present in the area.