Portsmouth is a city located in the county of Hampshire on the southern coast of England, and is the UK's only island city. It is commonly nicknamed Pompey. The administrative unit itself forms part of the wider Portsmouth conurbation, with an estimated 442,252 residents within its boundaries, making it the 11th largest urban area in England. At the 2001 census it was the only city in England with a greater population density (4,639/km² (12,015/sq mi)) than London as a whole (4,562/km² (11,816/sq mi)), although many of London's individual boroughs had a much greater density.