estany de l'Illa

Estany de l'Illa is a small glacial lake in the Vall de Gerber, within the municipality of Alt Àneu in Pallars Sobirà, in the Spanish Pyrenees. Sitting at 2,453 metres above sea level on the edge of the Aigüestortes i Estany de Sant Maurici National Park, it belongs to a family of high-mountain lakes that draw hikers looking for quiet trails away from the park's busiest corners.

What will you see at the lake?

Estany de l'Illa covers roughly 2.45 hectares, stretching 215 metres in length and 162 metres in width, with a shoreline of just under 700 metres. Its bed is granite, typical of this part of the Pyrenees, and it's fed by runoff from the slopes of the Los Tres Puis massif, which rises to 2,824 metres. The surrounding landscape is stark high-mountain terrain — bare granite slopes, sparse alpine vegetation, and open views toward the neighbouring peaks. The lake drains into the nearby Estany Redó, from where the water flows into the Noguera Pallaresa river and eventually into the Segre-Ebro system.

How do you get there?

The main approach trail runs about 11.26 km round trip, requiring roughly 6 hours to complete. The route crosses genuine high-mountain terrain, so it calls for solid fitness, proper trekking footwear, and a weather check beforehand — conditions in the higher reaches of the Pyrenees can shift quickly. Near the lake stands the Refugi de Gerber-Mataró, a mountain hut that can serve as a rest stop or waypoint along the way.

When is the best time to visit?

Given the altitude and alpine character of the terrain, summer through early autumn is the best window, when the trails are clear of snow and daylight hours are long enough for a comfortable round trip. In spring and late autumn, snow can still linger in the upper valley, making the approach considerably harder.

Who is this hike for?

This is a route for experienced hikers used to multi-hour treks in mountain terrain. The reward is a quiet high-altitude lake, raw views of the Los Tres Puis massif, and a real sense of distance from the crowds that gather in summer at the more famous corners of the Aigüestortes National Park.

Frequently asked questions

How long is the trail to Estany de l'Illa? The main approach trail is about 11.26 km round trip and takes roughly 6 hours to walk.

Is there anywhere to stay near the lake? The Refugi de Gerber-Mataró mountain hut sits nearby and can serve as a base or rest stop.

Is the lake inside the national park? Estany de l'Illa lies on the edge of the Aigüestortes i Estany de Sant Maurici National Park, surrounded by typical high-mountain scenery for the region.

Where does the lake's water come from? It's a glacial lake fed partly by runoff from the Los Tres Puis massif (2,824 m); excess water drains toward Estany Redó and on into the Noguera Pallaresa.