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Trekking in the Oca Mountains

Located in the Burgalesa region of Mounts of Oca, a short distance from the town of Villafranca Montes de Oca, is hidden among the enormous rocks that make it up, the imposing Gorge of Oca, carved into the rock by the tireless flow of the river, today conditioned by the Alba Dam. A place, that of the Mounts of Oca, furrowed by not few paths and ancestral ways as the Jacobeo.​

Gorge of the Oca - Route of the High Oca PRC-BU 55

The route of the Desfiladero del Oca - Ruta del Alto Oca PRC-BU 55 in its 9,2 Km combines the spectacularity of the narrow gorge with the beautiful landscape that offers the forests that populate these mountains, without forgetting the history that accompanies them reflected, for example, in the Hermitage of Our Lady of Oca, from where the route starts. A route that takes us to furrow the wild Gorge of the Oca, to later find us with the old layout of the Route of the High Oca PRC-BU 55, which will accompany us in almost all the route. Together we will approach, crossing the Alba reservoir, until the ruins of the old town that gives it its name, for once imagined its aspect in other times to set course until the spectacular Alba beech forest. A route that makes us go up the course of the river Oca which flows at our feet creating another narrow and wild gorge.

Beech forest of Alba

A channel that shortly before its birth we will cross to return towards our point of departure by the opposite slope of the dam of Alba while we look back to contemplate the rounded mountains of the Mountain range of La Demanda. We go up and down the slopes of the rugged crags under which the river Oca fits. Places that shelter colorful forests and fields in addition to enclaves as the one of the Lagoon of Valliciruelas or the hill on which the old Castro de Somoro settled, a privileged enclave from which a wide panoramic view is dominated. The High Oca Route PRC-BU 55 on its way back to Villafranca Montes de Oca leads us before saying goodbye to it until we reach the end of our path where the mythical San Indalecio Fountain awaits us. This is an obligatory stop before putting an end to this hiking route in the Hermitage of Our Lady of Oca, from where we start.

Alba Reservoir

The Legend

Legend has it that where today is located the Fountain of San Indalecio, was the place where this saint was martyred to death. That where his blood fell began to flow the water that today is a precious spring and that in the stones even today you can see the red spots of the blood of San Indalecio, unequivocal proof of the reality of the events that took place here.

How to get to Nuestra Señora de Oca Hermitage

The N-120 road that links Logroño with Burgos passes through Villafranca Montes de Oca. You can also get there from the north if you come from the N-1 or the AP-1 by taking the BU-703 road between Prádanos de Bureba and Castil de Peones. There is a daily bus service that stops at Villafranca Montes de Oca on the Burgos-Logroño-Zaragoza route. Once there the access to the Hermitage of Nuestra Señora de Oca will be found shortly after leaving Villafranca Montes de Oca in the direction of Burgos, or just before arriving if we come in the opposite direction. This old road, besides being the access to the hermitage, also leads to the Alba Dam. To get to the hermitage and the parking area next to it we have to deviate from the road that leads to the dam.

​​Pet area, hiking with my dog

We'll probably have to give our friend a hand to save some rather steep area of the gorge. For the rest it is a nice stroll in which we should not let him campar too much to his widths since it is easy that he can get to get lost.

Although we have to pass by several zones where our dog will be able to drink without problems we cannot leave us his corresponding ration of water and food, since we are before a demanding route for him.

It is not very common to run into other animals, but not impossible. The areas of thick vegetation that we are going to pass make it advisable that, as on the other hand we should always do, we take a look at our companion in search of parasites or wounds.

Description of the route of the Gorge of the Oca - Route of the High Oca PRC-BU 55

From the Hermitage of Our Lady of Oca to the Alba Dam 1,8 Km

The large parking area next to the Hermitage of Our Lady of Oca (0h 00min), is the starting point and arrival of this circular route that will lead us through the incredible places that are hidden in this area of the Mounts of Oca.

We begin next to the hermitage of Our Lady of Oca.

Walk a few metres along the track that leads us here, looking for the beginning of the path that we must follow.

We change course

Right in front of the hermitage door we radically changed course and began to gain altitude with ease.

We approach the Oca Gorge

This path, which we must not abandon at any time, leads us without complications to the beginning of the gorge.

We begin the real route by the Gorge of the Oca

Our path comes to an end at the same time as the walls of the gorge begin to close over us. A narrow trail will be in charge of guiding us in this area of the route.

The trail has no major complications

Trail that in some cases is carved in the rock forcing us to advance with caution. We have to find some pass, which although it does not have great difficulties, it does make this stretch even more interesting.

We cross the Oca River

The wildest area reaches its end at the same time that a bridge makes it easier for us to cross the bed of the Oca river. On the other side there is a wide and conditioned path that continues in search of the Alba dam.

The path is greatly simplified

Not much later we will come across a barrier (0h 15min) and its corresponding sign announcing the prohibition of passage for anyone alien to the facilities.

We follow the road that leads to the Alba Dam

Here, paying attention to the indications, we should go back to the hermitage to go to the nearby road that ascends to the car park of the Alba dam, where we will take our route again.

We arrive at the Alba Dam

Those who under their responsibility disregard the prohibition and follow the perfect walk in which we are at this point will quickly reach the base of the huge dam.

The stairs

There, steep stairs begin that go up the side of the dam until reaching its highest point.

We go up the asphalt track

Once you get to the top you only have to follow the road that leads to the Alba Dam. At the top of this asphalted track, after crossing the relevant barrier, we will join those who, paying attention to the signs, climbed up here along the road that ascends from the surroundings of the hermitage.

We joined the PRC-BU 55

Already together we connect with the battered layout of the PRC-BU 55 or High Oca Trail (0h 40min). ​

From the link with PRC-BU 55 or High Oca Trail to the Somoro Castro Detour 5,3 Km

A PR that takes us to cross the limits of the reservoir following the path that borders it.

We follow the path

A path that makes us lose height quickly, warning us of the continuous rise and fall that characterizes this hiking route in Burgos. The path follows the winding course of the reservoir until it takes us to one of its arms.

We follow the path at all times

Here our way besides forking also seems to reach its end while we continue bordering the limits that the water has marked.

We follow the path on the left

This short stretch leads us to the small stream of Montecillo, where the path ends definitively, and where we also find the short detour that leads to the ruins of the old village of Alba (1h 00min). Those who dare to cross the scarce 50 m that separate us from it will only have to follow the trail that runs next to the bed of the stream.

We continue on the left

In the past, our path did not end here, it continued almost without deviating, crossing from side to side the cultivation field that now cuts off our path, forcing us to turn radically to the left. As soon as we cross the stream we have to border the estate.

Following the route is complicated

From now on we will have to be very attentive as the orientation is complicated by the lack of signs and the number of trails that we will run into.

Now on the right.

Once you have passed the limits of the farm, turn right and continue bordering it on the outside. What looks like an old road can serve as a reference to follow in this section.

Vegetation doesn't make it easy

Although a little further ahead the vegetation swallows it making us look for the best way to continue advancing.

This area is one of the most complicated to follow the route

Once up and without having separated us in excess of the course that we maintained in the ascent we will find, hidden by the vegetation, the continuation of the way that on having passed the stream had disappeared under the field of cultivation that closed the passage to us.

The path leads us now

Already if so many complications follow the furrows that the road draws on the ground. Shortly after, the vegetation surrounding the San Millán stream warns us of our arrival there.

We crossed the creek

From now on, a narrow trail will be in charge of guiding us.

Our trail follows on the left

After crossing the stream, the path turns sharply to the left to continue bordering the reservoir from afar.

Better by the footpath above

This area, very entangled by vegetation, has different paths that usually run parallel to save more comfortably this area.

We arrive at Beech forest of Alba

Soon the first beeches next to some solitary mark of the PR warn us of the proximity of the Beech forest of Alba (1h 20min). Walking through this small beech forest is a spectacle that compensates the efforts made to reach it.

We travel without complications the beech forest of Alba

The trail, hidden beneath the litterfall, does not make it as difficult as before to follow it. In addition we will also have some marks that still resist the passage of time.

Better by the path on the left

Even so, and when we come out of the beech forest, we will continue to find various options that make us choose among them the path to follow.

The path takes us out of the beech forest of Alba

Outside the beech forest, the option we chose before, apparently more comfortable than the other will take us to the top of the hill we are about to cross.

We're approaching a ravine

Luckily this area has a more treaded path that will serve as a reference to follow and that leads us directly to a kind of ravine.

It is better to enlarge by the right

When arriving at its height, our footpath saves this depression of the land without detours, but if we look carefully to our right we will be able to see how the true layout will allow us to pass without difficulties this zone in exchange for extending a little more the route and to draw a wide curve.

The path blurs under the grass

Again together we continue to gain a few meters more of the lost height at the same time that the path is blurring under the grass. We will see ourselves heading towards a small pine grove as we intuit the path to follow.

The path is seen again

But before reaching the pines again the path reappears before us, taking us to the left, approaching the ravine where the river Oca flows.

We go through the wire fence.

A little further on we cross the wire fence which, if it had gone straight on towards the pines, would have cut us the pass.

The different options of paths to follow return

We then began the fast and muddy descent to the Oca River. A descent that could not be otherwise is plagued with trails that will not make it easy to follow the right course.

The descent if it is muddy is complicated

To our left, a small hill can be used as a reference because it is on its hillside where our route runs and most of the trails that descend towards the Oca River.

We head towards the Oca River

Once down most of the trails come together again to take us to the riverbed. We will have to cross the river to continue with the route.

We continue on the left

As soon as we cross it, we will come across two paths, one going straight ahead and the other, the one we have to follow, turns to the left to start a demanding ascent that will make us recover the lost height.

The steep slope is demanding

This demanding stretch, less exposed than it originally seemed, makes us gain height quickly, leaving beautiful views of the gorge that now runs to our left.

We're approaching the top of the hill.

The trail leads us to the top of a hill to join with the path we had seen some time ago when we were going to the Oca river bed. Once at the top of the hill we will see each other once more, without any reference to guide us, as the path and the footpaths we are following disappear under the grass.

We're still on the right, losing height.

At this point we will have to turn to our right going towards the limits of the forest that there is to border it by the left.

The road makes it easier for us to follow the route

A little further on, the battered road that has to accompany us in this part of the route appears before us once again. Already without so many complications at the time of orienting ourselves we see ourselves once again losing height to arrive at the, in general, dry bed of the Arroz Quemado stream.

We continue to descend

On the opposite hillside of this small ravine we can already see the marked path we have to ascend.

A new ramp begins

Once again we will see ourselves struggling to gain height with every step we take. Without marks or signs to guide us, the path is the only ally we initially have at our side.

We went out onto a wide dirt track

Once up, we will come across a wide dirt track that we will continue along, saying goodbye to our way that turns to follow its course.

We arrive at the crossroads with the detour to the lagoon of Valliciruelas

Not much further on we will reach a new crossroads where we will have to follow the path on the left, abandoning the wide track we were walking. At the moment a new junction appears in front of us, it is the detour that leads to the Valliciruelas Lagoon (2h 30min), a lagoon that unfortunately is not easy to find with water.

We follow the path without complications

We continue on our way, leaving this detour aside and entering a beautiful forest. Forest that quickly leaves us in a clear grassland delimited by an old enclosure.

We detour to the Castro de Somoro

Just at the vertex of this fence, we should find the battered sign that warns us of our arrival at the detour that leads to Castro de Somoro (2h 35min).​

We go up the hill to reach the castro

Castro that we will arrive at if we continue straight following the diffuse way that continues crossing this pasture. To then cross the hill in front of us on its left and climb to it gaining height. This height will bring us closer to the castro, which has disappeared under the vegetation, where we will be able to enjoy a magnificent panoramic view.

From the detour Castro de Somoro to the Hermitage of Our Lady of Oca 1,3 Km

Returning to the point where we took a detour to visit the castro, we resumed our route heading towards the grove while we bordered the edge of the estate that separates us from it.

We're heading into the woods

A couple of trees mark the gateway to the lush forest that awaits us. In this forest we will find the missing mark of PR-BU 55 or High Oca Trail as it is also known.

In front of a nice stretch through the forest

This section, as it could not be otherwise, is a typical route covered by leaves, which fortunately does not present complications to follow it.

We leave the road

Although we will have to be attentive since not much later we will run into the detour that we must follow and that makes us leave the road we were walking. A short trail takes us to a new path after crossing a fence.

We bid farewell to PRC-BU 55 or High Oca Trail

This road quickly takes us to another crossroads where we will say goodbye to PRC-BU 55 or High Oca Trail that continues its course towards Villafranca Montes de Oca while we continue descending on the left.

We arrived at the detour towards the Fountain of San Indalecio

Once again the river Oca comes to greet us at the same time that we meet another small detour, which leads to the nearby San Indalecio Fountain (3h 05min).​

We arrive again at the Hermitage of Our Lady of Oca

After visiting this place of legend we cross the river to face the last meters that separate us from the car park and the Hermitage of Our Lady of Oca (3h 10min) from where we begin this circular hiking route through the lands of Burgos.

Technical data sheet of the route

ico-distancia-totalDistance. 9,2Km

We can lower this figure by not going as far as the various detours that are presented to us.

ico-tiempo-totalTime. 3:10h

This figure will be increased by approximately 50 min more, which is what will take us back to the hermitage, and along the road that leads to the dam and the junction with the beginning of the PR-BU 55 or Alto Oca Trail.

ico-calendarioTime of year

The fog is not a good travel companion and less on routes of difficult orientation. Autumn and spring are the periods of greatest beauty when the itinerary crosses the forests that populate this area. A lot of caution in periods of rain or thaw, the dam can release more water than expected and the beginning runs through its natural drainage. In addition, mud can also complicate our passage in some areas.

ico-materialRequired equipment

The map of the area, the compass and the GPS with the corresponding track is something essential, together with knowing how to use this material, to be able to make this route with certain guarantees not to get lost. Water and food can not be missing in our backpack as we will not have fountains along the route. Footwear and appropriate clothing for a generally muddy terrain and walking sticks, should also accompany us in this activity. Consult our list of material and equipment for hiking. Read more.

ico-dificultadDifficulty. Moderate


Although the distance is not too noticeable, the continuous ups and downs, with some other ramp of entity, mark this section forcing us to have a good physical form to face the route without making us very demanding at the end.

Severity of the environment

It is necessary to emphasize the necessity of not venturing into the gorge without knowing beforehand the state of the Alba dam, since we can find sudden avenues of water that can put us in danger. In addition, this short stretch is not exempt of possible stone falls that could affect us. The rest of the route is not exempt from certain difficulties generally marked by the state of the terrain where mud can play a trick on any of the descents. The wading of the different streams will also be points where we can find certain complications depending on the flow they carry.


This is the section that adds the most difficulty to this hiking route. The PR-BU 55 or High Oca Trail is a path in Burgos that has been dehomologated and therefore has no maintenance and, although there are many people who walk through it, we will come across points where there is no reference whatsoever to follow, forcing us to pull the map and the information we have of the itinerary in order to continue with the route without getting lost in the attempt. In addition in many occasions we will find a good number of different footpaths that will make it even more difficult for us. Therefore it is not advisable to do this activity with bad weather or visibility and without a minimum knowledge of orientation.

Important places to pass through
1-Hermitage of Our Lady of Oca 0:00h 974m 0 Km 30T 474302 4691093
2-Limit of the dam 0:15h 980m 0.8Km 30T 473997 4690576
3-PRC-BU 55 Link 0:40h 1083m 1.8Km 30T 473191 4690904
4-Alba's depopulated detour 1:00h 1018m 3.4Km 30T 473633 4689883
5-Beech forest of Alba 1:20h 1069m 4.2Km 30T 474060 4689462
6-Detour to the Valliciruelas Lagoon 2:30h 1116m 6.8Km 30T 474744 4690060
7-Detour Castro de Somoro 2:35h 1088m 7.1Km 30T 474491 4690172
8-Castro de Somoro 2:45h 1109m 7.5Km 30T 474152 4690290
9-Detour Castro de Somoro 2:50h 1088m 7.9Km 30T 474491 4690172
10-Fountain of San Indalecio 3:05h 970m 9Km 30T 474329 4690866
11-Hermitage of Our Lady of Oca 3:10h 974m 9.2Km 30T 474302 4691093

Coordinates UTM Datum WGS84

Profile of the route

Profile Route Gorge of the Oca Route of the High Oca PRC BU-55

ico-desnivel-acumuladoSlope: 820m

ico-desnivel-positivoSlope +: 410m

ico-desnivel-negativoSlope -: 410m

ico-altitud-maximaMaximum altitude: 1118m

ico-altitud-minimaMinimum altitude: 970m

Cartography, maps and tracks

Oca Gorge Route Map - High Oca Route PRC-BU 55

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 map Route Gorge of the Oca Route of the High Oca PRC BU-55


This schematic with the path is approximate and has been created from the derived cartographic base © Instituto Geográfico Nacional "Cuadrante 201-4, 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.

Alba Dam
Ancient fountain of the uninhabited area of Alba
Fountain of San Indalecio
Gorge of the Oca
Hermitage of Nuestra Señora de Oca
Mountains of Oca
Villafranca Montes de Oca
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Listado de experiencias
Fernando Vazquez
Created the 11-12-2017

Una ruta muy bonita, una pena que en algunas zonas el sendero no esté bien señalizado.

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¿Did you know that...

The route of the PR-BU 55 or High Oca Trail starts in the same village of Villafranca Montes de Oca and, following the course of the French Way of Saint James, ascends the first ramps of the Mounts of Oca. It then crosses the national road and heads towards the Alba Dam and from there returns to Villafranca Montes de Oca, bordering the reservoir and the rocks that form the gorge of the Oca River.

Don't miss out...

The panoramic view that can be enjoyed from the site of the old Castro de Somoro. The detour to it barely adds 1 km to the total route and the views that can be enjoyed more than compensate for the effort involved in climbing the hill where the castro was located, a castro that can be sensed under the undergrowth that populates its remains.


Go to 8 Routes of Hiking in Burgos to get excited

Go to Hiking equipment What to bring?


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 29-11-2017. 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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