Route of El Entremón

  • Estimated time :1 h to the Mediano Dam (route out only)
  • Distance :2,9 km
  • Total Climb-descent :Climb: 138 m; Descent: 121 m
  • Altitude :Maximum: 519 m ; Minimum: 460 m
  • Type :Linear
  • Difficulty :Easy. Risk narrow passages without railings
  • Itinerary :Well signposted and defined.
  • Track/road type :The entire route follows paths. Passages without railings




Low difficulty, but you have to go through several steps closer and no railing, so there is risk of precipitation vacuum.

El Entremón pass, Ornithology Trail, Mediterranean woodland, the defensive buildings in Samitier, El Grado Reservoir, the Mediano Dam.


La Miranda Cave and the cromlechs of Los Yermos del Cementerio (the Cemetery Wasteland), both of which are close to the route but are not open to visitors at present.


The waters of the River Cinca are first stored in the Mediano Reservoir before being released into the remarkable El Entremón pass. For millions of years, erosion has shaped the limestone mountain, creating the canyon we will be visiting. Holm-oak forests and birds of prey overhead will feature on our walk, as will the memory of the peoples who chose this area of Sobrarbe during the Neolithic Period and the Metal Ages as their home and a place to pursue their agricultural and pastoralist way of life.

Road directions to starting point: in Aínsa, take the A-138 main road in the direction of Barbastro. After 18 km, you come to the Mesón de Ligüerre, where the highway to the left heads towards La Fueva Valley. After the first 3 km, before you enter the town of Ligüerre de Cinca, you come to a bridge over the El Grado Reservoir.

Starting point: once you have reached the far side of the bridge over the El Grado Reservoir, park your vehicle in the small car park to the right of the road. If you are travelling in a group with two vehicles, you could consider leaving one of them in the town of Mediano.

This route begins at the car park next to the bridge over the River Cinca, where there are a number of information panels concerning El Entremón and La Fueva. A wooden arrow points the way we should go, along the highway heading east. Two minutes or 120 m after you set off, you come the start of the path named "Congosto del Entremón" (El Entremón Pass).

Rising high above us are the rocky escarpments of Picatiecho rock. La Miranda Cave is on the south-facing side. Given the difficulty of reaching the cave and in the light of the need to preserve it, the cave is not open to visitors at the moment, but it is worth knowing of its existence, as it is an important archaeological site dating from Neolithic times (5000-3000 BC). It was here that the first agriculturalists and pastoralists in Sobrarbe lived. New settlers arrived later in the Early Bronze Age (1800-1500 BC). These people were already using metal to make a range of tools and other objects.

From the start, it is obvious that the itinerary is well signposted, as it is part of the Historic Route of the GR 1. It is also an Ornithology Trail, equipped with information panels that will help us to discover the fascinating world of birds. In fact, birds associated with rocks and crags are a constant presence along the entire walk, among them common griffons, Egyptian vultures, golden eagles and lammergeyers.

The path wends its way for the next ten minutes along the narrowest stretch of El Entremón. Even though the sides look sheer, this has not prevented holm oaks and other species typical of Mediterranean areas, such as box, juniper, lentiscus and laurustinus, from thriving here. The north-south orientation of much of the pass, plus its narrowness, has given rise to very unusual climatic conditions. Temperatures do not vary as much as elsewhere, frosts are not as hard and there is greater exposure to sunshine in the pass, which has encouraged clearly Mediterranean plant life here.

We come to the first information desk with details of Las Palomas Cave, situated opposite us. From this spot, you can admire the impressive rocky outcrop on which the defensive buildings of Samitier, the village's castle and church, were built in the 11th century.

At this point, the path begins to narrow and makes its way along a stretch excavated in the rock. As you advance, the pass widens and holm and gall oaks appear more frequently.

After the first 20 minutes, you come to the most spectacular stretch of the route, the Media Caña (Split Cane) Pass. As the limestone faces are sheer, a small walkway open on one side has been excavated in the rock. Be careful here, as any slip could prove fatal. This pass is followed by another, although in this case metal steps have been anchored in the rock. The damp and coolness of this spot provide perfect conditions for the Pyrenean primrose (Ramonda micony), a rock-loving plant with thick, hairy leaves.

Once you have completed this beautiful and exciting stretch, the path continues northwards. The waters of the River Cinca are becalmed by the El Grado Reservoir, flooding the bottom of the pass. Prior to completion of the Mediano Dam in 1959, El Entremón Pass was much feared by nabateros due to the rapids, whirlpools and the high risk of coming to grief against the rocks. During the spring thaw, these men would descend on rafts made of tree trunks, transporting the wood from the valleys in the peaks of the Pyrenees to the Ebro River and the Mediterranean Sea.

The Mediano Dam can be seen in the distance after 35 minutes' walking. The final stretch of this path is a gentle descent down to the panel that reads "Final Ruta Ornitológica", indicating the end of the Ornithology Trail. To reach the dam itself, continue along the path up a steep climb. When you come to the main road, turn right and make your way through three tunnels. The last of these brings you out at the Mediano Dam itself. To get to the top, you must climb up a metal staircase.

One hour after you set off, you have reached the final point on the route, the Mediano Dam. Rising above the water in the reservoir is the church tower of the village of Mediano. When the water level drops sufficiently low, its esconjuradero is exposed. This small construction built on a square floor plan was intended to ward off storms, which were much feared. Even so, it was unable to prevent the flooding of the village and the valley.

The backdrop to this view is the lofty massif of Monte Perdido and Peña Montañesa.

Near Mediano there is another extremely interesting archaeological site, known as the Yermos del Cementerio (Cemetery Wasteland). Even though it is not open to visitors at the moment, because it lacks the necessary signposting and protective measures, it is worth mentioning in the context of this route. The site has six stone cromlechs or circles dating from the Bronze Age (1800-700 BC). Thanks to archaeological excavations, it is believed that these circles were used for holding funerary rituals and as places where the ashes of cremated bodies were buried.

Retrace your steps back along the same path to return. If you are travelling in two vehicles and left one in Mediano, return there to where you parked it.


You must take drinking water with you and wear walking boots.