In 1973 Ray D. Lyons of the Colorado Archaeological Society followed up local tales of a “robber's roost” and discovered this rock fort, used by Native Americans for an estimated 4,500 years. Utes, although not usually fort builders, may have erected or enhanced this fortification during their encounters with palefaces.
Overlooking the site of the 1870s and 1880s agency, this fort measures about 600 feet long and 200 feet wide atop a narrow natural stone rampart. Inside is a 20-by-25-foot room, with an entry area to the west separated by a low rock wall with access at each end. Rock walls with wooden supports rise 6 feet to enclose the space where the natural stone does not rise that high. Four guard pits lie along the entry trail, which climbs across a talus slope, and two more mark the trailhead.