Portsmouth is a port city in Hampshire, England, mainly on Portsea Island, 70 miles (110 km) south-west of London and 19 miles (31 km) south-east of Southampton. It is the United Kingdom's only island city and has a population of 205,400. The city forms part of the South Hampshire built-up area, which also covers Southampton and the towns of Havant, Waterlooville, Eastleigh, Fareham, and Gosport.