Lac d'Estom, Glacial lake in Hautes-Pyrénées, France.

Lac d'Estom is a glacial lake in the Hautes-Pyrénées at 1,804 meters elevation, surrounded by high mountain peaks. The water is exceptionally clear, allowing views deep into the lake basin.

The sources record no historical events for Lac d'Estom itself; the lake lies in the Lutour valley, also called the Estom valley, above Cauterets in the Lavedan. Its documented setting is the refuge d'Estom on its shore, beneath the pic d'Estom Soubiran (2,829 m) and the pic de Labas (2,946 m), within the Pyrenees National Park.

The valley below the lake is also called the Estom valley, after the Lutour stream that runs through it above Cauterets. The lake lies within the Pyrenees National Park, and the Estom refuge stands on its shore, a stopping point for walkers heading on to the Arraillé pass or the Oulettes de Gaube refuge.

From the La Fruitière parking area at 1,371 m, the lake is reached in under two hours. The walk is very easy and well marked, on a wide path that is never very steep. From the lake, routes continue to the col d'Arraillé and the Oulettes de Gaube refuge at 2,151 m.

Lac d'Estom lies at 1,804 m and reaches a depth of 18 m, with a surface of 6.7 ha. Above it rise the Pic d'Estom Soubiran (2,829 m) and the Pic de Labas (2,946 m). From the lake, paths lead over the Col d'Arraillé (2,583 m) to the Oulettes de Gaube refuge below the Vignemale.