Monte Pissis, Extinct volcano in La Rioja Province, Argentina

Monte Pissis is an extinct stratovolcano on the Catamarca–La Rioja border whose main summit reaches 6,795 m. Its upper part holds several snow-covered peaks above a dark, shadowed lower slope, and its north face is largely glaciated.

The first recorded ascent was made in 1937 by Polish climbers Stefan Osiecki and Jan Alfred Szczepański of the Second Polish Andean Expedition; the mountain was not climbed again until 1985. A 1994 Argentine expedition using GPS claimed 6,882 m, but a 2005 Austrian DGPS survey found 6,793 m, confirmed by later surveys.

The name was given in 1885 by the Chilean Desert Exploration Commission under Francisco Javier San Román, honoring the French geographer Pedro José Amadeo Pissis, who served the Chilean government. The Quechua name Pillanhuasi is also recorded for the mountain, and the surname happens to match the Cacan word pissi, meaning "small".

The climb usually takes place between December and March when weather conditions are most stable. Most expeditions start from Fiambalá and establish several high camps on the way to the summit.

A large glacier system sits at around 5,900 meters elevation and feeds several small meltwater streams during summer. These ice fields are among the highest permanent ice masses in the Atacama Desert.