Alejandro Selkirk Island (officially Isla Alejandro Selkirk, aka Mas Afuera Island) is the largest and most westerly in the Juan Fernandez Archipelago (Chile). It is located in the southeastern Pacific Ocean, approx 180 km (112 ml) west of Robinson Crusoe Island.
The island is named after the marooned (as a castaway) sailor Alexander Selkirk (aka Alexander Selcraig, 1676-1721). He lived alone on the Juan Fernandez island (aka Mas a Tierra) for a total of 4 years and 4 months and is thought to have inspired Daniel Defoe for the main character in his "Robinson Crusoe Island" novel (published 1719). All that the sailor had left with him was some clothing, a musket (muzzle-loaded firearm), gunpowder, some carpenter's tools, a knife and a Bible.
The island measures roughly 11 km (7 ml) by 6 km (4 ml), with a total area of 50 km2 (19 ml2) and population under 100. Densely wooded and mountainous, Isla Alejandro Selkirk is marked by ridges and deep ravines leading to a steep and rugged eastern coast, where the cliffs reach heights of 1 km (3280 ft). The island's southern, western and northern coasts are with sandy beaches. The highest elevation (Cerro de Los Innocentes) is in the southwestern part (1,65 km / 5413 ft). This area also features a prominent rock with a large hole through it.
Wildlife on the island is represented by Juan Fernández fur seals, Masafuera rayadito (among South American's rarest birds, only around 140 individuals are left), feral goats.
Alexander Selkirk Island cruise terminal
Cruise ships to Isla Alejandro Selkirk anchor at approx 480 m (0.3 ml) northeast of the Sanchez Ravine (located off the eastern shore). This is the landing point with a boat slip and several buildings. Depths in the anchorage area are 31-50 m (102-164 ft), with a sand bottom.