Chiloé Island and the Chonos Archipelago are a southern extension of the Chilean coastal range at Chilean Patagonia, which runs north and south, parallel to the Pacific coast and the Andes Mountains. The Chilean Central Valley lies between the coastal mountains and the Andes, of which the Gulfs of Ancud and Corcovado form the southern extension. Mountains run north and south along the spine of the island. The east coast is deeply indented, with several natural harbors and numerous smaller islands.
