UN 13,166 is sequenced with UN 13,308 and unranked 13,179. One-way mileage and elevation gain are measured from the summit of UN 13,179. Round-trip mileage and elevation gain assume completion of the sequence.
The remainder of the ridge over to UN 13,166 from UN 13,179, which is another 1.8 mile away, is almost all an easy stroll over tundra. The rocky little summit of the peak had us wondering how we would make the top as we approached. Near this summit block, we paused for some photos of a large, conglomerate pinnacle and right at the base of the summit cliffs, we found a beautiful assortment of King’s Crown and Old-Man-On-the-Mountain that we had to photograph. Along with some bluebells and orange colored lichen on the conglomerate rock, it made for some colorful photography. The summit cliffs seem to rise vertically a good 75 feet or more above you here. Direct ascent would require technical gear, so head north, along the western base of the cliffs on a use trail and intersect the north ridge that connects over to San Luis. Once on the ridge, walk south along the eastern base of the rocky summit cliffs, but now the cliffs only rise about 30 feet above you. On this northeast side, there is a crack/weakness colored with plentiful orange lichen that you may ascend one at a time to the summit. The climb up is an unprotected ascent on very secure, conglomerated rock with plenty of holds. No need for rope in our opinion. From this summit you'll enjoy an excellent view of San Luis Peak, which could easily be climbed from here.
After a leisurely break, if weather allows, head back. The fairly long haul calls for taking the easiest way back you can find. You're in luck because the Continental Divide/Colorado Trail crosses the ridge just north of this summit and leads all the way back to near the trailhead. Drop north off the summit and hike down along the ridge, dropping west and onto the Colorado Trail as it heads westward toward San Luis Pass. This trail looses some elevation as it heads west through the head of the first basin or the eastward fork of Spring Creek. As we made our descent from the summit and then picked up the trail, we were entertained by an interesting sight. All along the western side of UN 13,166, there is a display of conglomerate pinnacles and hoodoos in extraordinary shapes. The survey map provides no indication at all of these formations. In addition to these, the wildflowers all through here were abundant and we had to stop numerous times for photo opportunities, especially when we came across some fields of purple asters in the second basin, main fork of Spring Creek. In the second basin, after crossing the western most of the two stream forks, just a short distance beyond that crossing is a nice campsite in some timberline trees. It was just big enough for a one-man, or perhaps, two person tent. After there, the trail heads in through some trees, after having crossed a couple of miles of tundra expanse, then exits the trees and ascends west on a switchback toward the pass we had mentioned coming near at the beginning of this hike/sequence. The actual trail skirts north of what the map shows as something of a cone topping out at 12,580 ft.
You will need to leave the Colorado Trail before that cone to reach that pass at 12,300 ft., and after wondering a little through the willows, quickly pick up the other trail we suggested using to gain this ridge & pass to begin the hike sequence. On the way down, we found some vivid clumps of paintbrush and stopped to photograph them.
Links to other information, routes & trip reports for this peak that may be helpful.