Hong Kong (/ˌhɒŋˈkɒŋ/ (listen); Chinese: 香港, Hong Kong Cantonese:[hœ́ːŋ.kɔ̌ːŋ] (listen)), officially the Hong Kong Special Administrative Region of the People's Republic of China and commonly abbreviated as HK, is a special administrative region of China on the eastern side of the Pearl Riverestuary in southern China. With over 7.4 million people of various nationalities^[c] in a 1,104-square-kilometre (426 sq mi) territory, Hong Kong is the world's fourth-most densely populated region.

Hong Kong became a colony of the British Empire after Qing China ceded Hong Kong Island at the end of the First Opium War in 1842.^[16] The colony expanded to the Kowloon Peninsula in 1860 after the Second Opium War, and was further extended when Britain obtained a 99-year lease of the New Territories in 1898.^[17][18] The entire territory was transferred to China in 1997.^[19] As a special administrative region, Hong Kong maintains separate governing and economic systems from that of mainland China.^[20] Although the territory is now politically associated with China, a relative majority of the population self-identify as Hongkongers rather than Chinese.^[21]

Originally a sparsely populated area of farming and fishing villages,^[16] the territory has become one of the world's most significant financial centres and commercial ports.^[22] It is the world's seventh-largest trading entity,^[23][24] and its legal tender (the Hong Kong dollar) is the world's 13th-most traded currency.^[25] Although the city has one of the highest per capita incomes in the world, it faces severe income inequality^[26] and hosts the largest concentration of ultra high-net-worth individuals of any city in the world.^[27][28]

The territory has the largest number of skyscrapers in the world, most surrounding Victoria Harbour.^[29] Hong Kong consistently ranks high on the Human Development Index, and has one of the highest life expectancies in the world.^[30] Although over 90 per cent of its population uses public transportation,^[31] air pollution from neighbouring industrial areas of mainland China has resulted in a high level of atmospheric particulates in the region.^[32]