The lac Noir is a glacial lake located under the crest of the eastern slope of the Vosges mountains, at an altitude of 3,067 ft (935 m). High granite cliffs surround it. The Black lake's peat bog is 4000 years old, and it constitutes a relatively rare environment at altitude. It is characterized by a mosaic of natural habitats: stagnant water, peaty environments, and sphagnum spruce forest. Among the flora are the club-shaped Lycopod and the Lister with heart leaves. In terms of fauna, the site is also home to the speckled nutcracker and the European hare.