A local climber/biker discovered the cliffs at Mentmore in 1997. Climbers and outdoor enthusiasts in the Gallup area collaborated with the family who owns the property to make Mentmore a fun place to climb. Prior to development as a climbing area, the site was being used for illegal dumping. There is still a lot of broken glass and debris around the cliffs.
The cliffs are composed of a well-cemented uplifted shelf of yellow to tan Cretaceous Gallup Sandstone. In total, there are over 100 routes, usually 40' to 50' tall. Most of the routes are sport, with a few traditional in the mix. There are more than 50 bolted top rope climbs and 31 sport climbs, ranging in height from 25 to 45 feet with difficultly levels of 5.0 through 5.13.
Mentmore is comprised of two separate areas, the new area and the original area. Both contain single-pitch sandstone climbs, with numerous moderate routes. All routes have easily accessible top rope anchors and plenty of rap stations for easy anchor set up and cleanup. Most top ropes require short (under 4') slings.
Scott Halliday Guidebook (PDF)