Located in the Andes, Lake Futalaufquen is three-lobed, of glacial origin, and occupies narrow valleys between glaciated peaks.

Tourist facilities and the National Park headquarters and Futalaufquen village are there.

The Arrayanes River is noted for its scenery and sport fishing, especially for rainbow trout, an introduced species.

The lake flows through a narrow passage called the "Monster Narrows" (estrecho de los monstruos) into Kruger Lake, 461 hectares (1,140 acres) in size.

The Narrows acquired that name because of the large trout that can be seen in the crystal-clear water.