Chiloé (chēlōāˈ) [key], island (3,241 sq mi/8,394 sq km), a part of Los Lagos region, off S Chile. It is separated from the mainland by the Corcovado and Ancud gulfs and the Chacao Channel; the waters around the island are used as nursery by blue whales. It is the largest of the Chilean islands and the only one that has been successfully settled. A rainy climate favoring the growth of wet and dense evergreen forests makes it one of the world's last virgin frontiers. Nevertheless, the settlers have been able to raise wheat and potatoes and to export timber. The population is concentrated around Ancud and Castro; the former was totally destroyed and the latter badly damaged by an earthquake in 1960. Wrested from the natives by the Spanish in 1567, Chiloé was the last stronghold of Spanish royalists, who were not driven out until 1826.