Estany de l’Illa

Estany de l’Illa is a high-mountain lake in the upper Madriu-Perafita-Claror Valley, in Encamp parish, beside the staffed Refugi de l’Illa. A small island gives the lake its name, while a dam built between 1947 and 1955 makes it part of Andorra’s hydroelectric system as well as a striking alpine destination. The lake is not reached by road: the official route from Grau Roig climbs through the Pessons basin, crosses Portella dels Pessons and descends on the GR7. The route is classified for experts, so the lake is a demanding objective rather than a casual walk from the ski car park.

The surrounding landscape changes markedly along the approach. The trail begins in the Grau Roig sector at the Cubil car park, where a forest path leads west to Estany Primer de Pessons. From there, yellow trail markers pass Estany Forcat and the lakes of Solana before joining the GRP/GR7. The path climbs a steep, winding slope to Portella dels Pessons at about 2,819 metres, where the terrain opens to views over the Pessons glacial cirque and the Illa lake. The final leg follows the GR7 downhill to the water and the refuge below the dam.

Visit Andorra gives the route as 8.66 kilometres, with 790 metres of ascent and 392 metres of descent, and estimates three to six hours. These figures describe the mapped route from Grau Roig to the lake, not a complete return to the starting point. The route sheet also calls the trail expert-level. Visitors should therefore plan how they will return, continue to another refuge or connect with a longer trek; simply reaching the lake does not complete a circular day walk. A return over the same high pass involves additional distance and effort.

Elevation figures differ between sources. The official route sheet places the lake at 2,528 metres, while the IEA lake inventory lists about 2,513 metres and an area of around 13 hectares. The latter database is based on older aerial and topographic mapping, while route elevation figures may use different mapped points or vertical references. For practical planning, regard the lake as lying around 2,500 metres, and do not use a small difference between published values to infer the exact elevation of the trail, refuge or dam crest.

The dam has altered a natural glacial lake to support hydroelectric generation. The workers who stayed at the original refuge built the dam between 1947 and 1955, and water from the lake contributes to the principality’s power system. The result is both a mountain waterbody and a piece of infrastructure. Visitors should remain on established ground around the shore and dam, avoid interfering with any structures or water-control equipment and follow signs near the refuge. The small island is a visible geographic feature, not an invitation to wade or swim; the cold water and high-altitude setting make immersion hazardous.

Refugi de l’Illa stands below the dam and is a staffed mountain refuge, not a hotel or walk-in restaurant in the village sense. It provides a possible overnight stop on longer routes through the Madriu valley, but beds and services must be confirmed and reserved in advance. The Govern lists its staffed service every day from 1 December to 1 May and from the first Saturday in June to 1 November; outside those periods, groups of at least 15 may arrange a booking in advance. An old, unstaffed refuge section remains open year-round but has no services. These refuge dates are separate from access to the lake itself. Carry the supplies needed for the full route even when an overnight stop is planned.

The valley is protected and motor vehicles are prohibited on its hiking trails. From Grau Roig, the access authority describes two possible approaches toward the refuge: the Pessons route over Portella dels Pessons, or a Montmalús route that passes Estany de Coma Estremera before a fork toward the Illa refuge. Other trailheads exist from the Andorra la Vella, Escaldes and Encamp sides, but those are much longer valley routes. These approaches are not interchangeable short alternatives; compare ascent, distance, daylight and transport before choosing one.

The official safety guidance recommends walking routes above 1,700 metres between late June and late September, with the season potentially extending from May to October only when weather and ground conditions allow. Snowfields, storms, strong winds, poor visibility and cold can persist at the pass after summer begins in the valley. Check the forecast for the high route, carry navigation and appropriate layers, and turn back if conditions deteriorate. A marked path is easier to follow than an unmarked slope, but it does not eliminate exposure or the consequences of a late start.

The lake has no staffed admission gate or fixed visiting hours. Google and Tripadvisor searches did not surface an exact business-hours schedule for the natural feature, and the mapped water polygon carries no hours field. Access is nevertheless constrained by daylight, weather, trail condition and protected-area rules. The refuge has its own service schedule, distinct from lake access; confirm that separately if the route depends on an overnight stay. There are no ordinary shops or transport services at the shore.

Estany de l’Illa suits experienced hikers who want a serious high-mountain route and can plan the full journey, not just the point where the lake appears on a map. Families or less experienced walkers may prefer a lower Pessons lake route, which provides a shorter introduction to the cirque without crossing the high pass. Before leaving Grau Roig, confirm the route markings, return or onward plan, refuge status, weather, water and transport. The combination of glacial terrain, a historic dam and the small island makes the lake distinctive, but the effort and exposure are part of the visit and should be planned accordingly.