Lacs des Grand et Petit Neuweiher, reservoir lakes in the Vosges, France

The Lacs des Grand et Petit Neuweiher are two lakes in a glacial cirque of the Haute Bers massif, on the border of Rimbach and Oberbruck. The lower lake, the Petit Neuweiher, is held by a dam at 810 metres; the two bodies of water lie in series, separated by a narrow wooded strip, with forested slopes descending to the shoreline.

The two lakes occupy a glacial cirque hollowed out by a glacier in the Haute Bers massif. Their present form comes from two dams built in series to supply hydraulic power to local forges and then weaving mills. The dams were abandoned, the lakes ran dry and a farm was built on the bed; when the dams were rebuilt in 1858 the farm was submerged. The upstream dam was later entirely rebuilt during reinforcement works led by the Conseil général du Haut-Rhin.

The lakes are named Neuweiher, "new ponds", although they are old: the name marks the dams rebuilt in 1858, which replaced earlier structures. The two basins work in series, the upper feeding the lower, and both supplied water power to forges and then weaving mills in the Doller valley. A chalet near the Grand Neuweiher serves simple meals and rooms during part of the year.

The lakes are reached only on foot, via paths maintained and waymarked by the Club vosgien, including the GR5-E2 and its variants. From Ermensbach, a hamlet of Rimbach with free parking at its entrance, the chemin des pierres along the Neuweiherbach or the Hinterer Wald wood takes about an hour. Other routes come from Oberbruck via the Gressons, or from Rouge-Gazon. Hikers staying on the GR5 can see the lakes from a viewpoint with a picnic table below the Tête des Charbonniers.

The farm whose ruins appear at low water was submerged in 1858, when the two dams were rebuilt; the site had earlier been drained and farmed after the original dams were abandoned. The upstream dam was later entirely rebuilt by the Conseil général du Haut-Rhin.