Hong Kong (Chinese: 香港), officially the Hong Kong Special Administrative Region, is one of two special administrative regions of People's Republic of China, the other being Macau. The territory lies on the eastern side of the Pearl River Delta, bordering Guangdong province in the north and facing the South China Sea in the east, west and south. Beginning as a trading port in the 19th century, Hong Kong has developed into one of the world's leading financial centres.

Hong Kong was a Crown colony of the United Kingdom from 1842 to 1981 and was a British dependent territory from 1981 until the transfer of its sovereignty to the People's Republic of China in 1997. The Sino-British Joint Declaration and the Basic Law of Hong Kong stipulate that Hong Kong operate with a high degree of autonomy until at least 2047, fifty years after the transfer. Under the policy of "one country, two systems", the Central People's Government is responsible for the territory's defence and foreign affairs, while the Government of Hong Kong is responsible for its own legal system, police force, monetary system, customs policy, immigration policy, and delegates to international organisations and events.

Hong Kong is located on China's south coast, 60 km (37 mi) east of Macau on the opposite side of the Pearl River Delta. It is surrounded by the South China Sea on the east, south, and west, and borders the city of Shenzhen in Guangdong Province to the north over the Sham Chun River. The territory consists primarily of Hong Kong Island, Lantau Island, Kowloon Peninsula and the New Territories as well as some 260 other islands. While Lantau is the largest island, Hong Kong Island is the second largest and the most populated. Ap Lei Chau is the most densely populated island in the world.

Much of Hong Kong remains undeveloped as the terrain is mostly hilly to mountainous with steep slopes. Of the territory's 1,104 square kilometres (426 sq mi), less than 25% is developed. The remaining land is remarkably green with about 40% of the landmass reserved as country parks and nature reserves. Most of the territory's urban development exists on Kowloon peninsula, along the northern shores of Hong Kong Island and in scattered settlements throughout the New Territories. The highest elevation in the territory is at Tai Mo Shan, at a height of 958 metres (3,140 ft) above sea level. Hong Kong's long, irregular and curvaceous coastline also affords the territory with many bays, rivers and beaches. Lowlands exist in the northwestern part of the New Territories.