The starting point is about 100 m before the entrance to the Faunístico Lacuniacha Park.
This park is located in the Tena valley, about 23 km from the Col du Pourtalet. From the Pourtalet pass the Formigal ski resort and then the village of Escarrilla. 5 km after Escarrilla, turn right onto a winding road that climbs to Piedrafita, cross the village and follow the signs for "Parque Faunístico la Cuinacha" for about 2 km to reach the park.
Park at the first car park on your right, opposite a long farm building.
Note 01/07/2023: It seems that the first car park is closed outside the July-August tourist season. This field is owned by a private individual. You'll need to go up to the second car park, the Park car park, and then back down the road to the start.
(S/E) From the car park, cross the road and take the track that starts above the farm building.
Follow this track for about 1 km.
(1) On your right, spot a cairn indicating the start of an uphill path. This path climbs more or less along the barranco Feneros, there are no markings: you'll pass some old terraces and then climb up, staying at the bottom of this small valley.
After around 700m, pass under a fence. Spot a cairn above you in the axis of this small valley, and join it on the path which disappears at times into the meadow. As you go up, you come across a path that you ignore, then a slightly more marked path that you follow to the left until you come to a waymarked path.
(2) Follow this path on your left until you reach a crossroads on a flat area: you'll see a signpost with directions. This little flat spot is called El Sarronal, hence the name of the arch.
(3) Opposite you, follow the signs for "Arco Geotectónico de Piedrafita"; the path passes at the bottom of a scree slope, then climbs steeply on the left side of the scree slope to a rocky bar. At the foot of the bar, fork right and climb to the top of the scree. After a few dozen metres of ascent, you'll see the arch from below. Don't try to pass under the arch, as the slope is very steep; the path skirts the arch on the right and climbs above it.
(4) Return to the path in the opposite direction on the way down. Follow the same path as on the way up.
(2) Turn left towards "Ibón de Piedrafita". The well-marked and signposted path runs almost flat, passing over a depression and a sheepfold. It then crosses a sort of small pass and descends to the lake, turning into a track. Reach the Piedrafita Lake (1620 m), a good place to stop for a snack. Continue on this track, passing the small dam that closes off the lake.
(5) At the stream that crosses the track (barranco del Boj), turn right, following the signs. Follow the path down to the stream: in fact, there are several paths on the right and left banks of the stream, arriving at the same point. The left-bank path is better marked.
(6) Cross a track and take the path below: opposite, El Refugio de las Planas. The path continues for 800 m along the stream, first on the left bank, then crossing it several times, to reach the track leading back down to the parking lot. Turn left and follow the track, which curves to the right.
(7) Leave the track and take the downhill path on the left, which cuts a hairpin turn and serves as a shortcut. Rejoin the track and continue left. Reach the park entrance, then 100 m further on, the parking lot (S/E).
during the week. In the recommended direction it was very good, no difficulty in following the path with your eyes open. As we were in good shape, we pushed on to the punta castech above the lake - thrills guaranteed!