Avenc de les Comarques

Avenc de les Comarques is a natural sinkhole cave in the municipality of Sant Esteve de la Sarga, in the Pallars Jussà region of Catalonia, Spain. Also known as Graller de les Comarques, it sits in the Alsamora area, on the western edge of the Montsec d'Ares range — a limestone massif famous throughout Catalonia for its dense concentration of karst caves and shafts.

How to get there?

The cave lies at around 1,320 meters above sea level, on the north-facing slope of La Corona peak, close to the Serrat de la Tualdeta ridge, at the head of the Barranc de les Comarques ravine. This is genuinely mountainous terrain: you can drive as far as Alsamora or the other villages of Sant Esteve de la Sarga, but from there the approach continues on foot along mountain paths toward the Montsec d'Ares massif. A topographic map is worth carrying, since trail markings in this stretch of the Pyrenean foothills are sparse and the area sees relatively few visitors. Because the cave itself is a vertical system with drops and shafts inside, exploring the interior without caving experience and proper equipment is not advisable — this is primarily a destination for people interested in the geology and scenery of Montsec, and the underground sections are best left to organized speleology groups active in Pallars Jussà.

What will you see?

Avenc de les Comarques is carved into the limestone typical of the whole Montsec range, where water has slowly hollowed out a network of caves and karst shafts over thousands of years. The cave has two separate entrances. The upper one requires a short jump onto a ledge, followed by a 6-meter descent into a gallery roughly 30 meters long. The lower entrance opens into a 16-meter vertical shaft that connects to an inclined gallery around 28 meters in length. Altogether, the passages add up to about 58 meters, with a maximum depth difference of around 31 meters — a compact but technical system that calls for rope-descent gear. The cave was discovered and first documented in 1970, and no archaeological remains have ever been recorded inside it, suggesting it was never used by humans in earlier times. Just nearby lies another cave system, Graller Petit d'Alsamora, underlining how riddled with karst voids this section of Montsec d'Ares really is.

Even without going underground, the surrounding landscape has plenty to offer: the steep limestone flanks of La Corona and the view over the Barranc de les Comarques valley make for a rewarding off-the-beaten-path mountain walk.

When to visit?

Late spring and early autumn are the best times to explore this part of Montsec, when mountain temperatures are moderate and the approach paths are dry and passable. Summer days can get hot and exposed, so an early start is advisable. In winter, the altitude above 1,300 meters combined with rocky, exposed approaches often brings snow and ice, making the walk to the cave entrances considerably harder.

Frequently asked questions

What is Avenc de les Comarques? It is a natural karst sinkhole cave carved into limestone on the western edge of the Montsec d'Ares massif, in the municipality of Sant Esteve de la Sarga.

Can visitors explore the inside on their own? It's not recommended — the system includes vertical shafts and drops that require caving equipment and experience. The underground sections are best left to organized groups.

How long are the passages inside the cave? The combined passages measure about 58 meters, with a maximum depth difference of roughly 31 meters, reached from two separate entrances.

When was the cave discovered? Avenc de les Comarques was discovered and documented in 1970; no archaeological finds have ever been recorded there.