Hong Kong Island (Chinese: 香港島) is an island in the southern part of the Hong Kong Special Administrative Region. It has a population of 1,289,500 and its population density is 16,390/km², as of 2008. The island had a population of 3,000 inhabitants scattered in a dozen fishing villages when it was occupied by the United Kingdom in the First Opium War in 1842, and the City of Victoria was then established on the island by the British Force in honour of Queen Victoria. The Central area on the island is the historical, political and economic centre of Hong Kong. The northern coast of the island forms the southern shore of the Victoria Harbour, which is largely responsible for the development of Hong Kong due to its deep waters favoured by large trade ships.

The island is home to many of the most famous sights in Hong Kong, such as "The Peak", Ocean Park, many historical sites and various large shopping centres. The mountain ranges across the island are also famous for hiking. The northern part of Hong Kong Island together with Kowloon forms the core urban area of Hong Kong. Their combined area is approximately 88.3 km (34.5 sq. mi.) and their combined population (that of the northern part of the island and of Kowloon) is approximately 3,156,500, reflecting a population density of 35,700/km² (91,500/sq. mi.).

The island is often referred to locally as "Hong Kong side" or "Island side". This style was formerly applied to many locations (e.g. 'China-side' or even 'Kowloon Walled City-side') but is now only heard in this form and 'Kowloon side', suggesting the two sides of the harbour. (The form was once more common in Britain than now, such as 'Surrey-side' and is still seen in British placenames like 'Cheapside', 'Tyneside', and 'Teesside', not all of which have an obvious watercourse or boundary with actual sides.)

Colonial era

British colony

Hong Kong island became an colony of the British empire when in 1839-1842 defeated the Chinese in the Opium war. The island was populated by only an few thousand people when British empire colonized it, the island was described as being almost uninhibited.

Japanese invasion and occupation

The Second World War was a dark period for Hong Kong. In the 1930s, the British anticipated a Japanese attack on Hong Kong. As Wong Nai Chung Gap was a strategic important place of defence, large-scale defensive works were constructed there, including anti-aircraft batteries, howitzers, and machine gun nests.

The Battle of Hong Kong began on 8 December 1941. British, Canadian, Indian armies and the Hong Kong Volunteer Defence Forces resisted the Japanese invasion commanded by Sakai Takashi, which began eight hours after the attack on Pearl Harbor. However, the Japanese were able to take control of the Hong Kong skies on the first day of attack, outnumbering the defenders. The Britons and the Indians: retreated from the Gin Drinker's Line and consequently from Kowloon under heavy aerial bombardment and artillery barrage.

On 18 December, the Japanese had conquered North Point, reaching Wong Nai Chung Gap on the next day. English and Scottish forces and the Canadian Winnipeg Grenadiers vigorously defended the crucial point of Wong Nai Chung Gap, and for a while successfully secured the passage between Central and the secluded southern parts of the island. Japanese casualties were about 600. However, Allied forces there were ultimately defeated by the Japanese on 23 December, and Wong Nai Chung Reservoir was lost - the only one in Hong Kong at the time. As Wan Chai Gap had also fallen that same day, the British had no choice but to surrender.

Hong Kong was surrendered on 25 December 1941, thereafter often called "Black Christmas" by locals. The Governor of Hong Kong, Mark Young, surrendered in person at the temporary Japanese headquarters, on the third floor of the Peninsula Hotel, thus beginning the Japanese occupation of Hong Kong. Isogai Rensuke became the first Japanese governor of Hong Kong. Hyper-inflation and food rationing followed; and the Japanese declared Hong Kong Dollars illegal. The Japanese enforced a repatriation policy throughout the period of occupation because of the scarcity of food and the possible counter-attack of the Allies. As a result, the unemployed were deported to the Mainland, and the population of Hong Kong had dwindled from 1.6 million in 1941 to 600,000 in 1945.

Hong Kong Island 22°15′52″N 114°11′14″E / 22.26432°N 114.18709°E / 22.26432; 114.18709 is the second-largest island of the territory, the largest being Lantau Island. Its area is 80.5 km², including 6.98 km² of land reclaimed since 1887 and some smaller scale ones since 1851. It makes up approximately 7% of the total territory. It is separated from the mainland (Kowloon Peninsula and New Territories) by Victoria Harbour.

Technically Hong Kong Island is part of the Wanshan Archipelago.