Auckland is the largest metropolitan area in New Zealand, with a population of over one million. It is in the northern half of the North Island, on a narrow isthmus of land that joins the Northland peninsula to the rest of the North Island. In November 2010, four formerly separate cities were amalgamated. The four were Manukau City in the south, Waitakere City in the west, North Shore City in the north and Auckland City itself, on and around the isthmus.