Hike Robledo Mountain via Leasburg Slot Canyon Robledo Mountains Wilderness, NM

Feb 28, 2022 — After a few burly days in Big Bend National Park, I was looking for a more pleasant hike near Las Cruces on my way home, and Robledo Mountain fit the bill. You can easily approach this peak from the west using the dirt road system, but I was more interested in checking out a slot canyon known as Leasburg Slot Canyon (or Las Cruces Slot) on the peak's eastern slope, and then continuing to the summit of Robledo Mountain from the head of the slot. My local friend Kevin informed me this route was viable and quite nice, so I excitedly headed to the trailhead. This trailhead is just a pull-off on the east side of the Rio Grande River and any car can get there. Note that the west side road of the Rio Grande River is on private property, so crossing the river on foot is required. You may notice my attached map is a bit of a mess, which I'll explain more about later.

The river was barely flowing and I didn't even need to take my shoes off, but who knows what the conditions will be on any given day. I headed through some spiky plants and then did some light brush-dodging to reach the mouth of Leasburg Slot Canyon. The conglomerate formations within the slot are really nice and the zig-zags of the canyon last a surprisingly long time. After taking a bunch of photos and dawdling as I enjoyed this unique spot, I reached the point where the canyon opens up and located a social/animal trail on the left, leading me out of the drainage.

I could see Robledo Mountain's summit ahead, protected by limestone cliff bands. I figured my best option to avoid those cliffs would be to ascend to the peak's south ridge rather than head directly up its east face. After all, I had told myself I was looking for a more relaxed day. The route was mostly clear of brush and rocks, a pleasant slope ascent. There was some Class 2 as I neared the ridgeline as the terrain got more steep, and a short cliff obstacle added some light Class 2/2+ to reach Robledo Mountain's south ridge. An avoidable Class 3 section along the crest led to the summit, but the Class 3 moves were fun, solid, and short-lived.

I originally intended to return the way I came, but from the summit of Robledo Mountain I could see Lookout Peak to the north, a significant neighboring peak just a short walk away. I sighed, knowing I’d regret not summiting it, and continued along Robledo Mountain's north ridge after giving my sore legs a quick massage from days of dehydration and overuse. A few fun Class 3 moves on solid limestone cliff bands led down the north ridge, quite a nice little route, and I was back on a pleasant slope. This would probably be more fun as an ascent, but I didn't know better before attempting the route.

After reaching the northern base of Robledo Mountain, I continued north over a hump along the ridgeline that added a couple hundred vertical elevation gain, and then I found myself on a dirt road at the base of Lookout Peak. I followed the road a short time and then continued off-trail on easy terrain to the peak's summit, which had some radio towers or similar structures. I backtracked from Lookout Peak and made it back to its southern saddle.

Now to address the issue of my messy attached map. I left my green line descent mishap (a rough estimate, at least) so you can see what I actually did, and maybe avoid going that way yourself. I mapped out a rough sketch (purple line) of what would be a safer and easier descent route back into Leasburg Slot. The problem is that the conglomerate rock through which Leasburg Slot was carved forms a serious cliff that wraps around most of the east face of Robledo Mountain. The slot itself carved all the way through these cliffs without dryfalls, but that isn't the case for other drainages coming off Robled Mountain, as I learned. The green line follows my friend Kevin's recommendation, which I'll describe here. From the saddle, I dropped into a brushy drainage and continued descending, passing over a few fun Class 3 limestone obstacles before reaching a major dryfall. This dryfall can by bypassed on the right, and then leads back into the drainage, where a substantial overhung drop leads into the conglomerate formation. I didn’t want to trust the potentially unstable conglomerate rock—it looks stable, but its large rocks might pop out under the right pressure. Kevin warns this is a "scary step", but I wasn't in the mood for this kind of spice today. I decided to attempt the adjacent canyon, which required going up and over a hill and descending more conglomerate. This second canyon had a 20-foot dryfall and then who knows what else after it, so I decided to cut my losses and just traverse back to Leasburg Slot Canyon's head. My stats do not reflect my mishaps.

The purple line on my attached map is what I believe would work well as a descent route, leading as directly as possible from the ridgeline down to Leasburg Slot. I can’t describe it in detail since I didn’t go that way, but from below and on a satellite map, it looks like a perfectly viable option. I was happy to get a second walk through the slot canyon, anyway. So much for a relaxed day—but hey, that’s adventuring, I suppose!