Hong Kong , officially Hong Kong Special Administrative Region of the People's Republic of China, is an autonomous territory on the southern coast of China at the Pearl River Estuary and the South China Sea. Hong Kong is known for its skyline and deep natural harbour. It has a land area of 1104 km² and shares its northern border with Guangdong Province of Mainland China. With around 7.2 million inhabitants of various nationalities, Hong Kong is one of the world's most densely populated metropolises.