Hike Tosco Benchmark and Southern Big Maria Mountains Big Maria Mountains Wilderness Area BLM, CA

Dec 01, 2024 — Tyler and I set out to hike to Tosco Benchmark, tacking on a couple of unnamed summits to create a loop. Our approach uses an old mining road, but the majority of the hike is off-trail and pretty rugged. To reach our trailhead, we left Midland Road here (33.71674, -114.64285) and headed north on a decent road fine for Crossover SUVs, until the junction with our mining road approach choice. Although we likely could have driven farther, the road becomes only suitable for ATVs shortly after anyway. We started by hiking along this old mining road, with Tosco Benchmark poking out in the distance. The road dipped in and out of a wash a few times, and I recommend following it. Even though the drainage also leads to the same spot, there are a few obstacles within and the gravel is loose enough to get annoying.

As we made our way along the road, the gorgeous multi-layered cliff band of our peaks the day before surrounding South Maria came into view behind us. The road then began to ascend, and we made our way toward Peak 1707 via its east slope. The terrain became steep and pretty unstable as we ascended the steep slope. The ridge crest leading to Peak 1707 introduced some Class 3 on rotten rock, a totally unexpected obstacle for this innocuous-looking peak.

We continued onward to Tosco Benchmark, descending briefly through some arroyo-riddled terrain and then into a drainage with a few short dryfalls. We left this drainage before it bent west, and side-hilled into the major drainage that would take us to the north ridge of Tosco Benchmark. This drainage was covered in boulders, and there was some Class 2+ scrambling along the way up stacks of them. After we reached the saddle, we continued south, heading toward Tosco’s summit. We kept right of the trickier-looking crest, choosing a more resonable-looking gully that we eventually left higher up in favor of a slope. The slope was not too loose, but it did have many granitic boulder clusters that added a possibly avoidable low Class 3 move here and there.

Peak 2071 was our final summit for the loop, but it was set pretty far north, and we were separated by a ridge traverse. From the saddle on the north side of Tosco Benchmark, we started up a slope that looked more dangerous from below than it ended up being (Class 2). Along the crest, much of the Class 2/2+ obstacles could be wrapped around, but there were some fun sections that required easy scrambling. The base of Peak 2071 was guarded by a volcanic cliff, so we kept right to avoid it, using a weakness on the southeast side that led to the summit.

From the top of Peak 2071, we headed down its northwestern ridge, navigating some loose terrain and a final small cliff at the base of the peak. We reached the old mining road again, following it back to the cars.