The Purón river gorge is a narrow river canyon carved by the river between the mountain ranges of Árcena and Andara, on the border between Álava and Burgos. On the Alava side it is part of the Valderejo Natural Park, one of the great limestone landscapes of the western Basque Country, with rocky slopes, riverside forest and small waterfalls and pools in the narrowest section. From the point of visit a very closed valley is appreciated, with rock walls, paths of old communication and a humid environment that contrasts with the nearby moorlands. The route allows us to see the transition between the open landscape of Valderejo and the Purón corridor, cooler and shadier, where the river gains prominence and the relief becomes more abrupt. It is a route often mentioned in hiking guides in the area and appears linked to the network of routes in the Valderejo Natural Park, with a regular exit in Lalastra. It is also associated with the abandoned village of Ribera, which adds historical interest to the route due to the presence of remains of traditional settlements and old passes between provinces. The best time to visit is usually spring and early summer, when the flow and riparian vegetation best show the gorge. On sunny days, the early morning hours favor the light on the walls; in summer, the interior of the canyon is cooler than the open areas.
