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Pyrenean lake of Acherito, the Way of Freedom

In the heart of the Hecho Valley, where the Oza Forest and the Guarinza meadows join hands, one of the emblematic spots of the Western Valleys Natural Park awaits us, where the Pyrenean lake of Acherito is located. Surrounded by the steep peaks of the Pyrenees that protect and nurture it, this Pyrenean lake has the honour of being the most western of the Pyrenean lakes, as well as giving visitors a beautiful view that they are sure to keep for many years in their memories.

Pyrenean lake of Acherito

The route and its 8.4 km start from the parking lot, near the remains of the old House of the Mine, a border post of the Carabineros who protected and controlled the passage through the nearby border. Diverse have been the civilizations that from immemorial times have forged roads and mountain passes that communicate both sides of the Pyrenees. The Pass of the Palo route, with which we will coincide in a large part of the tour, has been one of the most important communication routes in the area as its backbone. First the Romans and their legions, then the pilgrims on their way to Santiago and later the people who, for various reasons, were forced to cross the Pyrenees in search of a better life, or even trying to save it, have travelled along these paths and tracks that now delight hikers and mountaineers. Our route goes up the Acherito Ravine accompanied by some of these paths that, like the GR 65, go up to the Pass of the Palo or to the Arlet Shelter. Little by little, and already inside the Las Foyas Ravine, we say goodbye to them to set off towards the real objective of this trekking route, the hidden Pyrenean Lake of Acherito.​

Oza Forest

Along the path we can enjoy the magnificent views offered by the area, the thickness of the Oza Forest, the unmistakable silhouette of Acher Castle, or the steep peaks that, like the Mallo of Acherito, watch over those who enter this area of the Pyrenees. As we walk we discover ourselves thinking about the ancient civilizations that populated these lands leaving their indelible mark in the form of megalithic remains, very abundant in this region. Dolmens such as Acherito or Ferrerías Norte, although far from this route, invite us to enjoy the millenary route that we are partly travelling through with maximum attention. The important natural and scenic value of the Pyrenean Lake of Acherito impregnates those who reach it, not without effort, making it even more difficult to say goodbye and return on our steps to the car park, next to the old border barracks, as so many people before us did but this time without the disturbing presence of the guards who patrolled the area.

Acherito Ravine

The Legend

The most ancient legends tell that the Pyrenean lakes are each inhabited by a fairy who guards and protects them. Each fairy has her own special ability, some with their velvety voices sing beautiful songs that seduce the listener, making them dive into the crystal clear waters of the lake where they disappear forever. Others are capable of altering the weather if someone disturbs them and turning a sunny summer day into a threatening and unpleasant storm. Some of them have helped mountaineers and shepherds in danger or disoriented by the fog or the blizzard, guiding them to safety, while others enjoy leaning out from the bottom of the lake into the crystalline waters of the surface to play at being seen among the bright sparkles. But the greatest mystery of all is to know what fairy awaits us in the Pyrenean Lake of Acherito.

How to get to Mine House

To reach the detour to the House of the Mine, we must first go to Hecho and Siresa, either from Puente la Reina de Jaca, on the road between Pamplona and Jaca, which can also be reached from Huesca, or from Ansó, following the road that links the valleys of Hecho and Ansó with the Roncal valley in Navarre. Once in Hecho we will have to head towards Siresa and continue, without turning off, the road that passes through this town up the course of the Aragon Subordan River, crossing the narrow Mouth of Hell Gorge. Without leaving the road we will arrive at the Oza Forest where we will continue without deviations the battered road that little by little is becoming an ample earth track that goes up the valley. When it seems to gain width we will find the detour that leads to the shelter of the mine. This wide and battered track will make us cross the river and soon after arrive at the mouth of the Acherito ravine where after crossing the stream that runs through it we will have a small parking area where we can park our vehicle and start the route.

Pet area, hiking with my dog

Interesting route for our dog in which we can get used to this kind of mountain tours. Demanding due to the unevenness to overcome but affordable thanks to the relatively short distance ahead.

The water on this route should not be an inconvenience, not only because of the lake we are going to, but also because of the proximity of streams, although in summer and early autumn we should not trust. It is important to take some food with you so that you can recover from the effort before you return.

The cattle is one of the kings of the area, besides we must not forget that we are in a national park with its specific regulations on pets. It is not a bad idea that after the route we take a look at it, to rule out possible parasites.

Description of the route to the Pyrenean Lake of Acherito

We start this trekking route, which will take us to the westernmost Pyrenean lake, in the car park (0h 00min) of the old House of the Mine.

We start the trekking route towards the Pyrenean Lake of Acherito

We will go back a few meters on the track that brought us here, as the path we must follow begins next to the bridge that crosses the stream that flows into the nearby river Aragon Subordan.

We're heading towards the fence

Several routes converge here, the GR 11, the GR 65 and the paths that lead to the Arlet Shelter or the Cunarda Pass. We leave the course of the stream on our left and head for the nearby cattle gate.

After closing the gate well, the path continues in front of us

Here, hopefully, we will only have to open the door and go through this usually muddy area. On the other side, almost hidden by the vegetation, continues the path that we must follow.

The path is clearer than it looks

This part of the route, which is somewhat decomposed, makes us gain height with a certain comfort, leaving the bed of the stream further and further away.

It's almost always better at the one at the top

There are several trails that we find, in many cases bifurcations that join again later, although not in all cases.

We are approaching the Foyas Ravine

The footprints of the trail we are following, and its continuous upward slope, can serve as a reference in case of doubt.

We go into the ravine

Almost without realizing it, we arrive at the mouth of the Las Foyas ravine and prepare to go up. The path continues to provide us with somewhat cobbled areas with others in better condition as we move forward with the new stream that we furrow on our left.

The unevenness is already evident

This area is already beginning to show us the slope that awaits us later. Some sporadic GR marks that accompany us next to the lonely stone landmarks indicate that we are going in the right direction.

We go straight ahead

Soon we arrived at the crossroads where we said goodbye to one of the other routes that accompanied us. We continued to go up the ravine leaving behind this junction.

Be careful not to miss the turnoff

Now we must be very careful, because a few meters after the junction is the place where we will have to cross the stream, as the route continues to the other side.

If you are confused, soon the ravine and the path will confirm it

It is quite easy to skip this detour since the path invites us more clearly to follow the slope we were on, and the milestones that the detour marks are not easy to see.

Although it seems that the path continues NOT THIS WAY

If we skip it, not much further on, the path will disappear at the same time as the ravine narrows, reaching a point where we will have no choice but to go up the left side of the mountain to recover the right path.

THIS YES, look out for the milestones

If, on the other hand, we have chosen the right itinerary as soon as we cross the small riverbed of the ravine, we will begin the steepest part of the route.

We climb up the opposite side of the ravine

The path now ascends leaving the ravine on our right. The unevenness is evident and forces us to make an effort with each step in order to advance.

Here better by the one below

Once again, different trails emerge before us that make us have certain doubts as to which will be the right one, although in practice they are all small shortcuts that seek to smooth out the slope.

Attention to the milestones, they will help us

In the steepest or most abrupt areas, the different routes are considerable, forcing us to choose the best option while keeping an eye on the landmarks that mark our route.

The slope does not stop

We continue to climb the ravine, gaining height with every step. The path describes a few zigzags, although it usually advances mercilessly along the slope of the mountain.

We rarely change orientation

The landscape around us more than compensates for the effort the route is putting on us. Little by little we are separating ourselves from the ravine without ever ceasing to gain height.

Here we continue on the left

After a while we arrive at a new crossroads where we say goodbye to the GR 65 that continues towards the Pass of the Palo while we radically change direction to head towards the Pyrenean lake.

We change orientation

This part of the route runs along the slope of the mountain we observed on our left as we climbed. From now on, we will find the steepest sections of the entire route.

We passed through the bushes

Although on the contrary, the unevenness will give us more of a break as well as not being so demanding anymore.

We crossed the mountainside

The path cuts through the mountainside at all times without, under normal conditions, exposing us more than we can handle.

Attention in some sections

Here, too, we will find diversions that join up again later.

It's easier than it looks

The steeper areas, although simple, will force us to take it easy.

The slope is also noticeable in some sections

The route in this area also has some hard ramps that will not let us advance comfortably.

Watch out when we get back

It is important, as always, to look back and take references that will help us not to be confused when we return. Since there will be several trails that we will find and some of them do not make things easier.

Time to catch your breath

After a while we will arrive at a pleasant stretch, much more comfortable and without so much unevenness. The path seems to lead us to a scree that we see ahead.

We go through the scree

As we suspected, we will soon find ourselves crossing this cobbled area in search of the hill in front of us.

It's still a long way to the Pyrenean lake

Once again the slope becomes more noticeable as we move forward thinking that the Pyrenean lake awaits us behind the hill.

We're saving every hill

But nothing is further from the truth, we still have a long way to go. We continue to overcome small hills, after which we hope our objective will emerge before us.

The Pyrenean lake of Acherito is resisting

But time after time we meet again the line that marks our path heading towards another fold of the mountain.

Here better by the trail

Already with hardly any constancy in the slope, we are progressing relatively quickly through the high pastures we are crossing.

This section is usually quite muddy

A couple of small streams force us to look for the least muddy way to overcome them. We are now facing the last effort that will lead us to the beautiful place that awaits us.

Now we're getting there.

After the next hill, we only have a few meters left to discover what is hidden a little further on.

We arrived at the Pyrenean lake of Acherito

The Pyrenean lake of Acherito (2h 00min) surprises us by fitting in between the vertical walls that protect it. Once here we have the possibility to follow the trail that borders it.

We go through the limits of the Pyrenean lake of Acherito

Cross its drainage and continue to go around it to return to the starting point and from there return to the car park (3h 15min) undoing the path that brought us here.

Technical data sheet of the route

ico-distancia-totalDistance. 8.4Km

We can extend the route by climbing one of the peaks that surround the lake.

ico-tiempo-totalTime. 3:15h

The time taken by the route will be marked by the time it takes us to overcome the unevenness that separates us from the Pyrenean lake and the time we will undoubtedly spend on it.

ico-calendarioTime of year

Being able to calmly enjoy the Pyrenean lake of Acherito and its surroundings as well as the landscapes that will surround us on the route is an important part of this trekking route in the Pyrenees. Autumn and spring, as long as the snow allows it, are magnificent periods that bring their spectacular touch to the mountains and forests adding without a doubt an additional plus. With snow, ice or bad weather, we must assess our knowledge and physical fitness as well as the conditions of the route before venturing out.

ico-materialRequired equipment

It is important, as always, to equip ourselves properly as we are in the middle of the mountain and the weather may change quickly turning a peaceful summer day into an unpleasant experience if we do not carry some warm and waterproof clothes in our backpacks. Besides, we cannot lack the necessary means and material to consult and follow the route if necessary. The walking poles, hiking boots, water and food along with protection against the sun should not stay at home or in the car either. Consult our list of material and equipment for hiking. Read more.

ico-dificultadDifficulty. Moderated


It is a short but demanding route with a constant unevenness from the beginning to which some higher level ramps are added. The distance that we have to cover is the one that will allow us to face the route with the calm that it requires so as not to create too many difficulties at little physical condicion that we have. Moreover, if time allows us, we can recover in the Pyrenean lake while we enjoy the beautiful place it is in.

Severity of the environment

Although initially the path does not go through areas that are too exposed, we will go through some more cobbled and abrupt sections where we will have to be careful and which may raise more doubts in people who are not used to this type of terrain. Of course, as long as snow or ice are not the main protagonists, in which case the exposure and difficulty are considerably increased. It is important to avoid going off the beaten track as we are in a mountainous terrain with ravines and steep slopes that can put us in trouble.


Signposted at the crossroads we will find the rest of the route hardly has any markings or landmarks of stones. Even at the beginning the cattle fence could confuse us or make us back. The place where we will have to cross the stream is another point of conflict and we can skip it with some ease. Otherwise the path is clearly stepped on and this makes it easier to follow the route correctly. The areas where we will come across different trails tend to coincide with the steepest or most uneven ones and these trails generally seek to save them in the best possible way by rejoining them later.

Important places to pass through
1-Parking 0:00h 1228m 0Km 30T 688181 4747288
2-Pyrenean lake of Acherito 2:00h 1875m 4.2Km 30T 687069 4749872
3-Parking 3:15h 1228m 8.4Km 30T 688181 4747288

Coordinates UTM Datum WGS84

Profile of the route

Profile of the route to the Pyrenean lake of Acherito

ico-desnivel-acumuladoSlope: 1336m

ico-desnivel-positivoSlope +: 668m

ico-desnivel-negativoSlope -: 668m

ico-altitud-maximaMaximum altitude: 1878m

ico-altitud-minimaMinimum altitude: 1228m

Cartography, maps and tracks

Map of the route to Pyrenean lake of Acherito

This sketch of the route is not made to scale nor does it contain all the information relating to the area, it is merely indicative.

Topographic route to the Pyrenean lake of Acherito


This schematic with the path is approximate and has been created from the derived cartographic base © Instituto Geográfico Nacional "Cuadrante 118-3 y 118-4, 1:25.000"

Senditur has manipulated the tracks to correct the aberrant points that may exist, caused by problems with the reception of the GPS signal. In any case the tracks are always approximate. SENDITUR encourages you to use the new technologies within your reach, using them as support and consultation in your activity, not basing the realization and orientation of the same only and exclusively on them, since they may see their functioning altered by very diverse causes, not functioning correctly and their indications may not be precise.

Castle of Acher
Mallo of Acherito
Oza Forest
Pyrenean lake of Acherito
Valley of Waters Tuertas
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Listado de experiencias
Created the 23-08-2017

Pirineos, cada ruta una nueva experiencia. Y sobre todo esta.

Roberto Ruiz
Created the 16-06-2017

Una ruta de senderismo en el Pirineo de Huesca muy recomendable entre otras cosas por el paisaje que te rodea, además está a un paso de la Selva de Oza

Cristina Sanz
Created the 20-12-2016

Muy recomendable, la ruta es relativamente sencilla, no muy larga y merece la pena subir, el paisaje es muy bonito.

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¿Did you know that...

Both in the period of the Spanish Civil War and in the subsequent World War, this area and its mountain passes, such as that of the Curnada Pass, witnessed countless refugees crossing the border between the two countries for various reasons, including fleeing from the dangers that threatened them.

Don't miss out...

The Oza Forest, is a natural area of incalculable ecological value composed of a lush forest of firs, pines and beeches, which has among some of its virtues with a rich biodiversity composed among others, in addition to the flora, by bears, badgers, vultures, eagles or otters. In addition to the remains of ancient cultures such as dolmens or old Roman roads.


Go to 8 Walks and excursions in Huesca

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Respect the Path Keep it clean

From the commitment of SENDITUR with Nature and the respect to the balance of the environment, SENDITUR urges you to travel in a responsible way, with low environmental impact and respecting at all times the Natural, Cultural and Social environment wherever you go.



Besides sharing with all of us your experience on the route we would be grateful if you could write to us to inform us of any erroneous or outdated information you may have found, or simply to let us know what you think at Thank you.

This route has been carried out in the field by SENDITUR on 31-08-2016. The route may vary greatly depending on the time of year, weather conditions and terrain, as well as the actions of third parties and the evolution suffered in the natural environment where it is located. All opinions, advice and/or assessments made by SENDITUR in their descriptions are for guidance only and are subject to and/or refer to the specific conditions of the specific day of the route, referring to that specific day, taken from trained people, with the appropriate experience and with a high level of physical and technical preparation as a reference, as well as correctly equipped.

All the times are approximate and take an orientative character, the stops have not been taken into account, no matter how small they are. All the information related to the route, texts, images, videos, maps, diagrams, tracks, towns, and places of tourist interest are published as a guide, and may not coincide with the current state of each place. Before undertaking any activity, assess your technical knowledge, your physical condition, find out about the weather and the variations that the route may undergo, equip yourself correctly, be prudent and responsible at all times, and do not exceed your capabilities. SENDITUR is not responsible for any misuse or inappropriate use of the comprehensive guides of its routes and/or publications as well as its electronic guides, nor for any variations in their descriptions for the aforementioned reasons, and recommends that everyone be responsible and prudent in carrying out the activity. We also encourage you to read books and specialised guides to complement the information described above.

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