Lac Vert, Glacial lake in Vosges mountains, France.

Lac Vert is a glacial lake nestled in the Vosges mountains at about 1044 meters elevation, spanning several hectares with depths reaching 17 meters in places. Steep mountainsides and coniferous forests surround the waters, creating a compact alpine setting.

Lac Vert lies at the foot of the Tanet massif, which rises between 1,000 and 1,290 m and overlooks the glacial cirques of Lac Vert and Lac des Truites. The lake was formerly known as lac de Daren, and locally as Grüne See in Alsatian and Voiche Mâ in Lorraine. It sits on the Alsatian slope of the Vosges, in the upper Munster valley.

The lake lies in the Munster valley on the Alsatian slope of the Vosges, below the Tanet massif. Its names record the borderland: Grüne See in Alsatian, Voiche Mâ in Lorraine, and formerly lac de Daren. The green tint that gives it its name comes from an alga that multiplies from late June to late July.

The lake lies at 1,044 m at the foot of the Tanet massif, which rises to 1,290 m and overlooks the glacial cirques of Lac Vert and Lac des Truites. Paths reach it from the Munster valley and from the Tanet site; the ground is steep and stony, so wear sturdy shoes and bring weatherproof clothing.

The water takes on deep green hues from June through July due to algae growth and the dense fir forests surrounding it. This visual quality makes the lake particularly distinctive during those months.