Welcome Friend! As you arrive to the Sierra de Guara, You are going to live and feel an extraordinary experience, because you arrive to a space privileged by nature, rock and water. Its extensive territory is recognized nationally and internationally by protection figures that emphasize valuable, unique and spectacular landscapes and ecosystems. Unique geological formations, rivers and ravines, exclusive flora species, exceptional forests and trees, great ornithological wealth and a human landscape that has left a peculiar heritage, with traces of the first signs of Humanity, make this space one of the most admired and desired in southern Europe. 

Guara is located on the southern edge of the Pyrenees, in the so-called pre-Pyrenean mountain ranges of Alto Aragón. It is located in the center of the province of Huesca, straddling four regions that are pleased to offer you their resources for the enjoyment of their own and visitors: 

Here in the Natural Park of the Sierra y Cañones de Guara, Government of Aragón (, you can consult all the general information you need, as well as the existing interpretation centers (Bierge, Arguis and Santa Cilia), and something very important , know that there is a Board of Trustees or governing board and a series of management instruments that serve to ensure the conservation and management of the natural resources of Guara, but also to promote sustainable development of the peoples and people who live here. 

It was in the 70s of the 20th century, when the growing influx of visitors to the Sierra de Guara -not always respectful of that wild nature-, raised the first voices that requested its preservation and led, at the end of the 80s, to the processing of a natural park that, finally, would see its declaration as a protected area in 1990: the Sierra y Cañones de Guara Natural Park. With an area of 47,453 hectares, to which are added 33,286 hectares of Peripheral Protection Zone, it is the Protected Natural Area with the largest surface area in Aragon, far ahead of other emblems of Aragonese nature such as Ordesa and Monte Perdido, Posets-Maladeta or the Moncayo. 

Spain’s membership in the European Union also entails a series of requirements and responsibilities in terms of conservation. The great values of the Sierra de Guara lead it to join the great framework of the preservation of natural spaces and species in Europe, the Natura 2000 Network. And also through two channels: Special Protection Area for Birds (ZEPA), for the Community Directive on Birds, and Place of Community Importance (SCI), by the Habitats Directive, In 2021 the Management Plans of these figures have just been approved , which make Guara a Special Conservation Area (ZEC), a European benchmark. 

Other international recognitions come to increase the broad curriculum of the mountains, since the Sobrarbe-Pirineos Geopark / Pyrenees Geological Park (, a figure of the United Nations Educational, Scientific and Cultural Organization (UNESCO), recognizes the extraordinary geological heritage of the Sierra de Guara sector, which is located in the southern confines of the Sobrarbe region. As you can see throughout the mountain range, the geopark figure fits perfectly with the essence of Guara, a large rock framework on which its renowned canyons have been carved. 


The Natural Park takes the name of Guara, a mountainous alignment of about 15 km in length that stretches in a west-east direction, between the Guatizalema and Alcanadre rivers. It is the place where the highest peak of the mountain range is located, the tozal de Guara (2077 m), flanking Guara, but with a north-south direction, are the mountains of La Gabardiella, Arangol, Balcez and Sebil, which are around the 1500-1600 m of altitude and are also part of the Park. 

The whole of the Sierra de Guara is a great calcareous massif, in which we will discover its limestones of marine origin – folded about 65 million years ago during the Alpine orogeny and shaped by karst processes – and, at its feet, gigantic accumulations of conglomerates on which the characteristic stacks (mallos) have been carved. As if it were a wall, the (mallos) stacks defend the south of the mountain range in the transition to the Hoya de Huesca and the Somontano. Who has not been attracted by the abysses in the famous stacks of Salto de Roldán, San Martín de la Bal d’Onsera, Vadiello or on the bridge of the Gorges between Colungo and Asque

The folds and fossils of limestone, karst -with its fields of sinkholes, chasms, lapiaces, caves and springs-, or conglomerate stacks, are part of some of the Places of Geological Interest cataloged by the Government of Aragon. To learn more, you can download their files at

Although, without a doubt, this privileged geology has river erosion as its protagonist. The rivers and ravines of Guara cut through the limestone and conglomerate reliefs, as if a knife were cutting a stick of butter, and are forced to pierce the deep canyons that have made Guara internationally famous and its great sporting descents. In the world of canyoning or canyoning, very few will not have heard of the following canyons: 

  • Flumen River: Palomeras, at the foot of the Salto de Roldán + its tributary of San Martín de la Bal d’Onsera. 
  • Guatizalema River: straits of the Palomar, under the waters of the Vadiello reservoir + tributaries as prominent as Lazas, San Chinés, Isarre … 
  • Formiga River: upper section and the very narrow Gorgonchón. 
  • Alcanadre River: Gorgas Negras, Barrasil and las Peoneras + its main tributary, Mascún and its tributaries (Raisén, Otín, La Virgen …) 
  • Isuala de Balcez River: upper section, Oscuros y Estrechos + tributaries (Alborzeral, Cautiecho …) 
  • Vero River: its series of gorges chained from Los Oscuros to Villacantal and the tributary Fornocal. 

Barranquismo | Asociación de Empresarios de la Sierra de Guara

Not only the quality of the water in the rivers of Guara, but also that of the complex of underground waters that circulate through the limestones and that gush in sources and springs, are included in the inventory of Fluvial Points of Interest / – / unique-fluvial-points where the Pillera de Nocito ravine, the Alcanadre river appear. (source and straits of Tamara), the river and source of Mascún, and the Vero between the Villacantal bridge and the Fuente ravine. The Isuala de Balcez river, from its source to its mouth in the Alcanadre river, is classified as a Fluvial Natural Reserve default.aspx#prettyPhoto 

More information about the rock formations and landscapes of the Aragonese Pre-Pyrenees in general, and the Natural Park in particular at


Guara is home to a rough and intricate territory. This fact, together with being in an area of climatic crossroads – the border between the cooler and humid environments in the north and the drier and warmer ones in the south – has led to a marked difference between the northern and southern slopes of the sierra. This phenomenon allows the existence of a great variety of species of flora and fauna, some of them at the limit of their Pyrenean distribution. 

Although most of Guara is included in a Mediterranean environment, 13.2% of its surface presents alpine, high mountain environments, as can be seen in the main summit of the mountain range and on its north face, where specimens still resist of black pine, beech and fir trees in the southernmost location of the Pyrenees, as if it were a window in Ordesa. The black pine and red pine forests, in many cases extended by the repopulations of the twentieth century, were also naturally present in some shady areas of the sierra, always accompanied by boxwood

But the most common forests of Guara are those of Mediterranean descent, made up of gall oaks and holm oaks or holm oaks that, until the mid-nineteenth century, covered a large part of its mountains. Today, of those oaks, some groves and magnificent isolated specimens survive, such as those of San Úrbez de Nocito, Otín and Bagüeste. The holm oaks also suffered intense exploitation (felling, charcoal, breaking …), which caused the disappearance or thinning of important extensions, replaced by kermes oak, juniper and black juniper. Some monumental holm oaks have come down to us, such as the millenary Lecina holm oak, collected in the Inventory of Singular Trees , and chosen European Tree of the year 2021. To learn more about these and other arboreal giants, you can also visit 

The millenary Lecina holm oak

Sheltered among the holm oaks and kermes oaks of the southern conglomerates of the mountains is an unimaginable variety of plants, such as labiérnagos, durillos, cornicabras and strawberry trees or alborzeras, shrubs that evoke ancient tropical laurels that millions of years ago covered Guara. However, 50% of the surface of the Park is occupied by shrub, especially above the forest, on the crests and culminating hills exposed to the wind, even to winter snows. It is the kingdom of the hedgehogs, a cushiony and thorny plant that, when it blooms in June, turns the Park yellow. 

In the rocky cliffs of stacks and canyons there are very specialized plants, adapted to verticality and extreme conditions, such as the king’s crown and the bear’s ear, and others exclusive to the mountains, such as the beautiful Petropcoptis guarensis, which adorns with its pink flowers, in spring, the calcareous walls of the Alcanadre and Vero canyons. 

corona de rey
The king’s crown

With regard to fauna – ornithology and bird watching have their own section on our LINK website – the Sierra de Guara serves as a refuge for a large number of animals. Among the mammals we can mention the wild boar and the increasingly abundant roe deer, which find refuge in the forest thickets of the Park. The feral goat population has grown. The fox, the marten or fuina, the wild cat, the weasel, the badger and, in clean water rivers, the otter are not lacking either. The cavities of the caves and chasms also serve as a refuge for several species of endangered bats. Some place names remind us of the presence of large mammals in distant times: the Bal d´Onsera or the Ballón d’a Lupera certify that bears and wolves were inhabitants of the mountains. 

The barbel catfish, the trout, the bermejuela and the water snake are the main inhabitants of the rivers, together with the native crab, in danger of extinction – it has a Recovery Plan to improve its populations -, without forgetting the Pyrenean newt or Guardafuens, a curious amphibian exclusive to the Pyrenees, found here at its southern limit of distribution. Other humid places shelter the frog, common toad, runner toad or the very few spotted toad and San Antonio frog, but also very rare reptiles, such as the Aesculapius snake, present in some beech forests in the Park. To complete this succinct list, we will cite some very valuable invertebrates vulnerable to habitat alteration, specifically coleopterans such as the alpine rosalia (beech trees) or the stag beetle and the great capricorn (oak and holm oak forests), or the butterfly Erebia lefebvrei abosi, discovered in 2017 and exclusive to Guara. 

More information about the geobotanical landscapes and botanical biodiversity of the Aragonese Pre-Pyrenees in general, and the Natural Park in particular at and at https: // www.