The Rachelsee at the foot of the Great Rachel, is the quietest Bayerwaldsee and can only be reached on footpaths. Like the Great Arber Lake, it is dominated by a steep sea wall.
The lake was created as a glacial Karsee, after the meltwater of the molten Rachel Glacier was dammed by a wall of moraines.
- Under the dark brown colored water surface hides a depth of 13.5 m.
- The 5.7 hectare lake is poor in aquatic animals and fish due to its lack of calcium salts and soil acidification.
- Around the lake around, since since the establishment of the nature reserve no tree was felled here, a primeval forest formed, which may be crossed only on a jungle nature trail.