Defektuzko Albistea

The range of Arno

The mountain range of Arno is located in the north-west of Gipuzkoa, though some of the more westerly slopes spread into the Historic Territory of Bizkaia. This area, situated in the municipal districts of Mutriku and Mendaro, is of immense scenic value, for which it has been put forward as a "Place of Communal Importance " (PCI) to be included in the Natural Network 2000.

The most striking aspect of the scenery is the dense blanket of Cantabrian evergreen oak that covers the slopes, hence the characteristic dark green colour of the range.

View of Arno and surroundings.

Despite the coniferous plantations that have sprung up over the last few years, Arno is one of the largest forest areas of Cantabrian oak in the north of the Iberian peninsula, and therefore constitutes a real natural treasure.

Turismo rural en Euskadi
Turismo rural en Euskadi

Olatz is a small valley approximately two kilometres in length enclosed in the heart of the Arno range. Access to the valley is up a small road that starts in Mutriku; it is on your left as you leave the town on the road leading to Ondarroa.

If there is one place in the region that brings together such historical significance in so little space, that place is Arno. Prehistoric traces of human presence are to be found in caves such as Langatxo and Iruroin, located next to the River Deba, near Astigarribia, or those of Jentiletxeta in the valley of Olatz.


  • From the neighbourhood of Astigarribia in Mutriku. The track - a former path on the Santiago Way - starts off from behind the disused lime furnace next to the road, and leads up to the pass of Apain.
  • From the pass of the Calvario, on the road from Astigarribia to Mutriku. Follow the track that ascends in a westerly direction. (It will take us approximately 50 minutes to reach the summit of Arno).
  • From Azpilgoeta in Mendaro. Take the track that leads up to the football pitch. It will take us approximately 1 hour and a half to reach Arno.
  • From Olatz, in Mutriku. Having followed the track that takes us to Korostola a path will then lead us up to Apain and on to the summit of Birulan.
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