Hong Kong, officially the Hong Kong Special Administrative Region of the People's Republic of China, is an autonomous territory on the eastern side of the Pearl River estuary in East Asia, south of the mainland Chinese province of Guangdong, and east of the special administrative region of Macau. With over 7.4 million Hongkongers of various nationalities in a territory of 1,104 square kilometres, Hong Kong is the fourth-most densely populated region in the world.
Hong Kong was formerly a colony of the British Empire, after the perpetual cession of Hong Kong Island from Qing China at the conclusion of the First Opium War in 1842. With the exception of the Second World War, during which the territory was occupied by the Empire of Japan, Hong Kong remained under British control until 1997, when it was returned to China. As a special administrative region, Hong Kong maintains a separate political and economic system apart from mainland China.
Hong Kong is one of the most significant global financial centres, holding the highest Financial Development Index score and consistently ranking as the most competitive and freest economic area in the world.