Eiao is the largest of the extreme northwestern Marquesas Islands. The island is uninhabited, but is administratively part of the commune (municipality) of Nuku-Hiva, itself in the administrative subdivision of the Marquesas Islands.
As of 2022, the only settlement on the island is a small shelter on the north coast of Vaithua Bay with a water tap. There are some small artificial structures in the north of the island, most likely for archeological purposes. There is a small shrine of Mother Mary somewhere along a trail to the plateau at the top of the island.
Geography
alt=A map showing numerous named locations on Eiao island.|left|thumb|Geographical map of Eiao
Eiao is a remnant of a caldera wall in a 5 million-year-old volcano, which measured . The island is a long and wide crescent shape, measuring .
It is often considered one of the biggest desert islands on earth.
The center of this island is the high Tohuanui plateau, rising on the east side to above sea level, much of which has been devastated by herds of feral sheep and other animals brought here by humans. This plateau is a red desert which covers around 50–60% of the island.
History
Pre-European
In pre-European times, the bodies of chiefs from parts of Te I'i were taken to Eiao for burial.
Eiao was once home to a Marquesan tribe called the Tuametaki. Archaeological investigations have discovered workshops for the production of stone tools, especially adzes, made from local basalt. These tools have been found in archaeological sites on other islands as far as Kiribati, providing evidence for prehistoric inter-island voyaging within this island group.
alt=Excavation of Tuamataki basalt mining facilities.|thumb|Eiao Excavation Sitesalt=Satellite image of Eiao island.|thumb|Eiao island from above.
Post-European Contact
The first non-Polynesian encounter with the island was in 1791 by the American sea captain Joseph Ingraham, who named it Knox Island in honour of Henry Knox, then US Secretary of War. Other names given to this island by Western explorers include Masse, Fremantle, and Robert. The island was uninhabited at the time of its "discovery" by Europeans.
Oral traditions and legends about the island include a story of a Peruvian treasure hidden there by some Spaniards. Other stories tell that during World War II, a German submarine arrived there secretly to hide a Nazi treasure.