Crystal Mill, historically known as the Sheep Mountain Power House, is a wooden power house built in 1892. It is a compressor station which generated compressed air to drill holes in the mine walls in the nearby silver mines and was used until the Mountain Sheep Mine closed in 1917. It was placed in the National Register of Historic Places in July 5, 1985.
The Crystal Mill is located above the Crystal River in Colorado, between the towns of Glenwood and Aspen, 6 miles east of Marble. It can only be reached during the summer and fall months via a road that requires a 4×4 vehicle, a sturdy pair of boots, a mountain bike or a horse.