Mentolat is an ice-filled 6 km (4 mi) wide caldera in the central portion of Magdalena Island, Aisén Province, Chilean Patagonia. It forms part of the Isla Magdalena National Park. Little is known of the eruptive history of Mentolat, but it is thought to be young, with a possible eruption in the early 18th century. On the infrequent occasions when the clouds clear, Mentolat overlooks the port town of Puerto Cisnes.