Kowloon is north of Hong Kong Island and south of the mainland part of the New Territories. The size of Kowloon is about 47 km² (18 sq mi). In law, Kowloon refers to the area south of Boundary Street and Stonecutters Island, leased to the United Kingdom by the Qing dynasty in 1860. In 1898, the Qing dynasty leased the New Territories to the United Kingdom for 99 years. New Kowloon, the area north of Boundary Street, is officially part of the New Territories. In modern culture, however, New Kowloon is part of Kowloon.