South Hampshire is a term used mainly to refer to the conurbation formed by the city of Portsmouth, city of Southampton and the non-metropolitan boroughs of Gosport, Fareham, Havant and Eastleigh in southern Hampshire, South East England. The area was estimated to have a population of over 1.5 million in 2013. It is the most populated part of South East England excluding London. The area is sometimes referred to as Solent City particularly in relation to local devolution, but the term is controversial.

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.