Castillo means castle in Spanish, and the steep basalt walls of the mountain indeed make it look like one.

An alternative is the excellent 4-day hike that starts on a spot called Las Horquetas Grandes on Carretera Austral, goes through forests, has two river crossings (no bridges), and goes over a 1,400 m mountain pass adjacent to the rock walls of Cerro Castillo.

Second ascent: February 4, 1976 Nick Groves (GB) with Mike Searle and New Zealand climbers Tom Clarkson, John Mayrick and Lauchi Duff repeated Chilean route and finished a 20 m under the summit.

Third ascent: December 5, 1982 Yugoslavs Tone Golnar and Ljubo Hansel, New Zealander David Waugh and South Korean Chil Kyou Son teamed together to make the first ascent of the southeast face of Cerro Castillo.

October 2003, first repetition of supercouloire on southeast wall Chilean climbers Pablo Crovetto, Rodrigo Fica and Spanish companion Eduardo Mondragón.