Mentolat is an ice-filled, 6 km wide caldera in the central portion of Magdalena Island, Aisén Province, Chilean Patagonia. This caldera sits on top of a stratovolcano which has generated lava flows and pyroclastic flows. The caldera is filled with a glacier. 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 that may have formed lava flows on the western slope.