Portsmouth is a port city and unitary authority in Hampshire, England. Most of Portsmouth is located on Portsea Island, off the south coast of England in the Solent. This means Portsmouth is the only English city not located primarily on the mainland. Located 74 miles (119 km) south-west of London, 50 miles (80 km) west of Brighton and Hove, and 22 miles (35 km) south-east of Southampton; Portsmouth is part of the South Hampshire conurbation. It is the most densely populated city in the United Kingdom, with a population last recorded at 208,100.

City status in the United Kingdom is granted by the monarch of the United Kingdom to specific centres of population, which might or might not meet the generally accepted definition of cities. As of 22 November 2022, there are 76 cities in the United Kingdom—55 in England, seven in Wales, eight in Scotland, and six in Northern Ireland. Although it carries no special rights, the status of city can be a marker of prestige and confer local pride.