Manchester () is a city and metropolitan borough in Greater Manchester, England. The city has the country’s fifth-largest population at 547,627 (as of 2018) and lies within the United Kingdom’s second-most populous urban area, with a population of 2.7 million, third most-populous county, at around 2.8 million, and third-most populous metropolitan area, with a population of 3.3 million. It is fringed by the Cheshire Plain to the south, the Pennines to the north and east, and an arc of towns with which it forms a continuous conurbation. The local authority for the city is Manchester City Council.

The recorded history of Manchester began with the civilian settlement associated with the Roman fort of Mamucium or Mancunium, which was established in about AD 79 on a sandstone bluff near the confluence of the rivers Medlock and Irwell. Although historically and traditionally a part of Lancashire, areas of Cheshire south of the River Mersey were incorporated into Manchester in the 20th century. The first to be included, Wythenshawe, was added to the city in 1931. Throughout the Middle Ages Manchester remained a manorial township, but began to expand “at an astonishing rate” around the turn of the 19th century. Manchester’s unplanned urbanisation was brought on by a boom in textile manufacture during the Industrial Revolution, and resulted in it becoming the world’s first industrialised city. Manchester achieved city status in 1853. The Manchester Ship Canal opened in 1894, creating the Port of Manchester and directly linking the city to the Irish Sea, 36 miles (58 km) to the west. Its fortune declined after the Second World War, owing to deindustrialisation, but the IRA bombing in 1996 led to extensive investment and regeneration. Following successful redevelopment after the IRA bombing, Manchester was the host city for the 2002 Commonwealth Games.

The city is notable for its architecture, culture, musical exports, media links, scientific and engineering output, social impact, sports clubs and transport connections. Manchester Liverpool Road railway station was the world’s first inter-city passenger railway station. At the University of Manchester, Ernest Rutherford first split the atom in 1917, Frederic C. Williams, Tom Kilburn and Geoff Tootill developed the world’s first stored-program computer in 1948, and Andre Geim and Konstantin Novoselov isolated the first graphene in 2004.