The walk to Vega Pociellu starts at L'Armadiella, about 2 kilometres before Tarna, in Caso, and is 12.7 kilometres there and back, rated easy, in about 4.5 hours. It passes the Ablanosa pasture and the Fabucao beech wood on the way to a glacial meadow with horses and cows.
At the southern tip of the municipality of Caso, near the Tarna pass, the Nalón is still a stream. That is where one of the quietest routes in the Redes Natural Park begins: the walk to Vega Pociellu, a meadow of glacial origin where horses and cows graze and the only sound is cowbells. It is 12.7 kilometres there and back, rated easy, through a mountain pasture and one of the loveliest beech woods in the park.
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Tarna, at the end of the valley
Tarna is the village in Caso that gives the pass its name. The Camino Real de Tarna ran through here, still serving as the road between the Meseta and Asturias in 1916, important enough that in 1775 the king was asked to make it passable again, and the main road did not open until 1935, according to Wikipedia. In La Foz there is a chapel from 1786 with the image of San Pedro that, tradition says, the flood of December 1774 swept there.
The river is born very close by: according to Wikipedia, the Nalón rises at the Nalona spring, at the Tarna pass, at 1,443 metres, and from there it flows down towards Campo de Caso, Laviana and the rest of the valley.
Where the route starts
According to asturias.com, the starting point is L'Armadiella, on the Tarna pass road, about 2 kilometres before the village, at kilometre 56. There is room for barely two cars there, so it recommends parking further back, in a larger area, and walking up the road to the forest track. The track has a sign forbidding unauthorised vehicles.
Right at the start you cross the Nalón on the Puente Corral, very close to its source, and the track runs below the Cuetu Negru, the mass that watches over the Ablanosa and Mongayu valleys. From the path you can see the Tabayón del Mongayu waterfall.
The Ablanosa pasture and the Fabucao beech wood
After about 3 kilometres you reach Ablanosa, a mountain pasture with a spring, well-kept huts and views east towards Peña Ten and Pileñes. Brañas are the high summer pastures, and asturias.com counts more than a hundred of them in Redes.
At Carrascosu the track turns into a footpath, roughly waymarked, and enters the Fabucao beech wood, which asturias.com counts among the loveliest in Redes. Coming out of the wood, Vega Pociellu appears: a glacial plain surrounded by the Sierra de Pries and the Sierra de Mongayo, with huts, pasture and free-roaming livestock. In the background stand the Cantu l'Osu, the Tiatordos and, further away, Brañagallones.
The way back and the variant
Most people return the same way: 12.7 kilometres in total and about 4.5 hours. There is an alternative return via the Collau Arenas, Fabucao, the Cerréu pasture, which is also a viewpoint, and Ablanosa, back to the car park; it adds about 4 kilometres.
When to go
In summer the pastures are in use and the meadow is full of animals. In autumn the Los Abedulosos slope turns colourful and is, according to asturias.com, at its best. In the cold months the mountain weather rules, so check the forecast before setting off.
For those who want to add the Tabayón
The waterfall you see from the route has its own trail. According to Turismo Asturias, the Tabayón del Mongayu route is a loop that starts and ends in Tarna, measures 11.66 kilometres, with 576 metres of climbing and between 3 and 4 hours; the fall is about 60 metres high and you can walk to its foot, after crossing the Monte Saperu beech wood. That makes two half-day outings for a weekend at the head of the valley.
Tips
Good footwear is needed, and the livestock roam free: walk past them without disturbing them. Part of the path is poorly marked, so download the route to your phone before setting off.
Checked
Facts checked in October 2026 against: asturias.com (Route to Vega Pociellu, Spanish and English versions), Turismo Asturias (Autumn in the Redes Natural Park: routes for everyone) and Wikipedia (Nalón river and Tarna).
Quick questions
Where do you park for Vega Pociellu?
There is room for barely two cars at L'Armadiella; asturias.com recommends parking further back, in a larger area, and walking up the road to the forest track.
Is there a different way back?
Yes, via the Collau Arenas, Fabucao, the Cerréu pasture and Ablanosa; it adds about 4 kilometres.
When is the best time to go?
In summer the meadow is full of animals, and in autumn the Los Abedulosos slope turns colourful.