Lake Llanquihue is the second largest lake in Chile with an area of about 860 square kilometres (330 sq mi). It is situated in the southern Los Lagos Region in the Llanquihue and Osorno provinces. The lake's fan-like form was created by successive piedmont glaciers during the Quaternary glaciations. The last glacial period is called Llanquihue glaciation in Chile after the terminal moraine systems around the lake.

Lake Llanquihue is located in southern Chile a territory of northern Patagonia in the Los Lagos Region. The lake's views of Volcán Osorno make the surrounding cities such as Puerto Varas tourism hotspots.