The Natural Park of Valderejo is located at the westernmost tip of Álava, right on the border with Burgos and right next to Montes Obarenes Natural Park – San Zadornil. It was declared by the Government of Spain in 1992 in order to protect a total of 3,418 hectares of land; being therefore the smallest natural park in the province.
This space of Valderejo is articulated around the channel of the Purón River, which flows through the less elevated terrains of the park between hillsides and steep limestone escarpments that end in showy crests. The erosion of its waters has favored the appearance of an interesting karst landscape in which the Purón River gorge -the most emblematic place of the whole joint- formed by high rock walls and waterfalls. It is a sparsely inhabited place with only a few population, some of them isolated since decades. This fact has undoubtedly contributed to the maintenance of Valderejo in its perfect state of preservation.
Historical heritage. It contains several megalithic monuments such as the Tomb of San Lorenzo or the Monolith of Monte Lerón.
Fauna. Valderejo contains the largest colony of griffon vultures in the Basque Country. Other common animal species in their territory are also common in northern Spain: the golden eagle, peregrine falcon, goshawk, roe deer, wild boar, wildcat or marten.
Itineraries. The park has a network of up to nine self-guided interpretive trails that run through the place. Of all of them, perhaps the most popular is the one that enters the Desfiladero del Purón from the town of Lalastra, also equipped with several recreational areas and a public parking.
Access. Valderejo is close to some places like Villanañe or San Millán de San Zadornil, in Burgos. Access to Lalastra is made from several secondary roads such as A-2622, which starts from A-1 and goes through many cities such as Salinas de Añana until it reaches the park.