Situated 670 km (362 nmi; 416 mi) off the coast of Chile, they are composed of three main volcanic islands: Robinson Crusoe, Alejandro Selkirk and Santa Clara.

The islands are primarily known for having been the home to the marooned sailor Alexander Selkirk for more than four years from 1704, which may have inspired English writer Daniel Defoe's Robinson Crusoe.

Robinson Crusoe is the second largest island in the archipelago at 47.9 km2 (18 sq mi); its highest peak, El Yunque, is 915 m (3,002 ft).

The islands are volcanic in origin, produced by the movement of the Nazca Plate over the Juan Fernández hotspot.

As the plate moved eastward over the hot spot, volcanic eruptions formed the Juan Fernández Ridge before being subducted under the South American continent at the Peru–Chile Trench.

"[12] The archipelago is very diverse in climate taking into account its size, this is due to factors such as its topography which causes the temperature and precipitation regime to change depending on the area of ​​an island.

[13] The wheater is moderated by the cold Humboldt Current, which flows northward to the east of the islands, and the southeast trade winds.

The Juan Fernández islands are home to a high percentage of rare and endemic plants and animals, and are recognized as a distinct ecoregion.

[17] The treeline is at approximately 950 m (3,100 ft), above which is alpine shrubland and grassland, dominated by temperate Magellanic vegetation such as Acaena, Dicksonia, Drimys, Empetrum, Gunnera, Myrteola, Pernettya, and Ugni.

Three endemic species dominate the tall and lower montane forests of the archipelago, Drimys confertifolia on both main islands, Nothomyrcia fernandeziana on Robinson Crusoe, and M. schulzei on Alexander Selkirk.

The Juan Fernández Islands have a very limited fauna, with no native land mammals, reptiles, or amphibians.

Robinson Crusoe Island is home to an endemic and endangered hummingbird, the Juan Fernández firecrown (Sephanoides fernandensis).

[19] All three islands of the Juan Fernandez archipelago have been recognised as Important Bird Areas (IBAs) by BirdLife International.

"[21] Ichthyologists Ingo Hahn and Uwe Römer wrote in 2002, "the geographically isolated Juan Fernández Islands were probably untouched by man until their discovery by European sailors in 1574.

[24] British and American whaling vessels were regular visitors to the islands, starting with the London (Captain Joshua Coffin) in 1795.

In his book Two Years Before the Mast (Chapter VII), Richard Henry Dana Jr. described the islands as he found them circa 1834.

However, when Dr John Coulter visited it in the early 1840s, he reported the island deserted after the approximately 1000 convicts had risen up, killing the soldiers and Governor who had held them captive.

[27] In 1908, the islands were visited by the Swedish Magellanic Expedition and Carl Skottsberg is believed to have been the last to have seen the Santalum fernandezianum tree alive.

Following the Royal Navy's win at the Battle of the Falkland Islands a month later, the only surviving German cruiser, SMS Dresden, was hunted down and cornered illegally at Más a Tierra early in 1915, although she was in Chilean territorial waters, where it was scuttled after a brief battle with British cruisers.

[32][33][34] As a commune, the Juan Fernández Islands are a third-level administrative division of Chile governed by a municipal council, headed by a mayor (Spanish: alcalde) who is directly elected every four years.