Olca is a stratovolcano on the border of Chile and Bolivia. It lies in the middle of a 15 km long ridge composed of several stratovolcanos. Cerro Minchincha lies to the west and Paruma to the east. It is also close to the pre-Holocene Cerro Paruma. It is andesitic and dacitic in composition, with lava flows extending several kilometres north of the peak.