Juan Fernández Islands, a group of three Chilean islands—Robinson Crusoe (formerly Más a Tierra), Alejandro Selkirk, and tiny Santa Clara—in the Pacific Ocean. They are about 400 miles (640 km) west of Chile. Total area is about 70 square miles (180 km2). The islands are volcanic in origin and mountainous, rising to 5,400 feet (1,650 m) above sea level on Alejandro Selkirk. The only settlement is San Juan Bautista, on Robinson Crusoe. Fishing is the chief economic activity.
Juan Fernández, a navigator in the service of Spain, discovered the islands about 1574. Alexander Selkirk, a Scottish sailor, was marooned on Más a Tierra, 1704–09. Accounts of his adventures inspired Daniel Defoe's Robinson Crusoe.