Caballo Mountain (10,496'), Los Alamos county's highpoint, used to have a well-established official trail up the mountain from the Guaje Canyon Trail #282
but the Las Conchas fire of 2011 torched the mountain's Ponderosa pine trees and subsequent flooding of the mountain slopes completely obliterated the trail.
In early 2019, a few local trail runners looking for the best, non-bushwhacking route up Caballo Mountain, began ascending this route, the Southwest Ridge of Caballo, because the ridge still has a number of unburned stands of Ponderosa pine trees and is relatively clear of obstacles.
This is a very steep, sometimes loose ridge that gains nearly 2,000' in a mile and a half. Ascending the ridge is, without a doubt, a grind, and descending the ridge can be tedious with some loose sections. It is not an official trail and is certainly classified as an off-trail route. That said, a number of cairns and cut/cleared trees mark the way and allow for straightforward ascent of this fine mountain. The view from the south-facing open, grassy slope just below the summit offers a sweeping vista from Espanola to the Valles Caldera.
The true summit of Caballo Mountain is officially in the Santa Clara Indian Reservation but an old sign near the top suggests it's fine to head to the summit so long as one is respectful. The summit is difficult to find due to the large number of fallen dead trees. But a couple of large rock cairns mark the approximate summit location. To find the summit cairns, the best route is to head east at the top of the grassy slope, just south of all the dead trees for longer than you think you should. Look for an orange forest service plastic post and enter the dead trees here. Navigate your way through the fallen trees to the north and west until the summit plateau area.