It is located approximately 350 kilometres (190 nautical miles) south of Java and Sumatra and about 1,550 km (840 nmi) north-west of the closest point on the Australian mainland.

With an area of 135 square kilometres (52 sq mi),[8] Christmas Island's geographic isolation and history of minimal human disturbance has led to a high level of endemism among its flora and fauna, which is of interest to scientists and naturalists.

The Anglo-Celtic influence in the capital known simply as The Settlement is closely tied to Catholicism, whereas in Poon Saan Buddhism is common, and Sunni Islam is generally observed in the shoreline water village where the Malays live.

[14] Captain William Mynors of the East India Company vessel Royal Mary named the island when he sailed past it on Christmas Day in 1643.

[17] English navigator William Dampier, aboard the privateer Charles Swan's ship Cygnet, made the earliest recorded visit to the sea around the island in March 1688.

An expedition crew were sent ashore with instructions to reach the summit of the plateau, but they failed to find a route up the inland cliff and were forced to turn back.

[16] In the next year, Pelham Aldrich, on board HMS Egeria, visited the island for 10 days, accompanied by J. J. Lister, who gathered a larger biological and mineralogical collection.

John Davis Murray, a mechanical engineer and recent graduate of Purdue University, was sent to supervise the operation on behalf of the Phosphate Mining and Shipping Company.

In 1922, scientists unsuccessfully attempted to view a solar eclipse in late September from the island to test Albert Einstein's theory of relativity.

[26] From the outbreak of the South-East Asian theatre of World War II in December 1941, Christmas Island was a target for Japanese occupation because of its rich phosphate deposits.

[27] During the night of 10–11 March, mutinous Indian troops, abetted by Sikh policemen, killed an officer and the four British NCOs in their quarters as they were sleeping.

About 850 men of the Japanese 21st and 24th Special Base Forces and 102nd Construction Unit came ashore at Flying Fish Cove and occupied the island.

[27] Isolated acts of sabotage and the torpedoing of the cargo ship Nissei Maru at the wharf on 17 November 1942[29] meant that only small amounts of phosphate were exported to Japan during the occupation.

[27] The United Kingdom transferred sovereignty of Christmas Island to Australia at the latter's request, with a $20 million payment from the Australian government to Singapore as compensation for the loss of earnings from the phosphate revenue.

[51] The Morrison government announced it would re-open the centre in February the following year, after Australia's parliament passed legislation giving sick asylum seekers easier access to mainland hospitals.

[59] The mountain was originally a volcano, and some basalt is exposed in places such as The Dales and Dolly Beach, but most of the surface rock is limestone accumulated from coral growth.

[60] The summit of this mountain peak is formed by a succession of Tertiary limestones ranging in age from the Eocene or Oligocene up to recent reef deposits, with intercalations of volcanic rock in the older beds.

[62] After months of consultation with local people, both parks were approved in March 2022, with a total coverage of 744,000 square kilometres (287,000 sq mi).

The park will help to protect spawning of bluefin tuna from illegal international fishers, but local people will be allowed to practise fishing sustainably inshore in order to source food.

Tropical cyclones also occur in the wet season, bringing very strong winds, heavy rain, wave action, and storm surge.

[11] Today, the plurality of residents are Chinese, with significant numbers of European Australians and Malays as well as a smaller Indian community, alongside more recent Filipino arrivals.

Since the turn of the 21st century and right up to the present, Europeans have mainly confined themselves to The Settlement, where there is a small supermarket and several restaurants, the Malays live in their coastal kampong, and the Chinese reside in Poon Saan (Cantonese for "in the middle of the hill").

[13] The main languages spoken at home on Christmas Island, according to respondents, are English (28%), Mandarin (17%), Malay (17%), with smaller numbers of speakers of Cantonese (4%) and Hokkien (2%).

[68] Religion in Christmas Island (2021)[69] Note that some statistical noise is added to the publicly released census data, in order to protect residents' privacy.

The territory falls under no formal state jurisdiction, but the Western Australian government provides many services as established by the Christmas Island Act.

Christmas Island remains constitutionally distinct from Western Australia, however; the power of the state to legislate for the territory is delegated by the federal government.

A unicameral Shire of Christmas Island with nine seats provides local government services and is elected by popular vote to serve four-year terms.

A number of islanders support self-governance, including shire President Gordon Thompson, who also believes that a lack of news media to cover local affairs had contributed to political apathy among residents.

The more widespread great frigatebirds nest in semi-deciduous trees on the shore terrace, with the greatest concentrations being in the North West and South Point areas.

[110] Insect species include the yellow crazy ant (Anoplolepis gracilipes), introduced to the island and since subjected to attempts to destroy the supercolonies that emerged with aerial spraying of the insecticide Fipronil.