The Inaccessible Island is an uninhabited island in the Atlantic Ocean, part of the Tristan da Cunha archipelago. With the other islands of the archipelago it is part of the British Overseas Territories of St. Helena, Ascension and Tristan da Cunha.
Together with Gough Island, it has been a UNESCO World Heritage Site since 2004. The island is classified as an Important Bird Area, reported by BirdLife International as a breeding place for seabirds and as a wetland protected by the Ramsar Convention.
Since 27 February 1997 the island and the surrounding waters up to 12 nautical miles have been a nature reserve. 24 species of birds nest on the island and it is a breeding ground for the subantarctic fur seal (Arctocephalus tropicalis).
The treeless grounds and rocky coasts are nesting areas for some pairs of Tristan albatross (Diomedea dabbenena), critically endangered species, the endemic spectacled petrel (Procellaria conspicillata), Moseley's eudyptus (Eudyptes moseleyi) and of the sooty albatross (Phoebetria fusca), all species classified as endangered by the IUCN, which find a habitat free of predatory mammals on the island, unlike Ghough Island where the allochthonous house mouse population poses a threat to the nests.
There are four resident terrestrial species, including the Inaccessible Island rail (Atlantisia rogersi), the smallest flightless bird in the world, the others are the Tristan thrush (Nesocichla eremita gordoni), two species of the Thraupidae family, the dove of the Inaccessible Island (Nesospiza acunhae) and the Nesospiza wilkinsi dunnei.
Other endemics present are the yellow-billed albatross, the prion-billed prion, the plumed petrel, the spectacled petrel, the Atlantic shearwater, the dusky shearwater, the barnacle stormbird, the white-bellied stormbird and the Antarctic tern.
The island is located about 40 km southwest of the coast of Tristan da Cunha and extends for about 5.7 km from east to west and 4.6 km from north to south, for a total area of about 14 km² . The coasts are steep and with few and short stretches of beach.
The island is a plateau that reaches its maximum altitude with 449 m a.s.l. of Cairn Peak; it is characterized by marshes and peat bogs, with short streams that give rise, on the east coast, to waterfalls directly into the ocean.
Nightingale Island, which is also part of the archipelago, is located 20km to the south-east; Gough Island is located 400 km to the south-south-east. The island is classified as an Important Bird Area (IBA), reported by BirdLife International as a breeding ground for seabirds and as a wetland protected by the Ramsar Convention. Since 27 February 1997 the island and the surrounding waters up to 12 nautical miles have been a nature reserve.