Hike Keystone Tower (Peak 2340) and Peak 2740 Kofa National Wildlife Refuge, AZ

Feb 27, 2023 — This being the final day of our Sonoran Desert trip, we were looking forward to a shorter outing with hopefully fun scrambling after the extended tour of the Southern Castle Dome Mountains yesterday. Our two-peak hike today would lead to the unnamed monolith Peak 2340 (which we renamed Keystone Tower due to its proximity to the Keystone Mine), followed by a ridgeline traverse over to the high point of this area, Peak 2740. I thought this was an excellent hike in a colorful and remote area of Kofa National Widllife Refuge. If you decide to skip Keystone Tower to skip the scary scrambling and instead just enjoy the views, this route would be reduced to Class 2/3.

Reaching the trailhead turned out to be far less rough than we thought it would be, but it's about an hour on mostly good dirt roads from pavement. Starting east on King Road here (33.26706352, -114.23900), we continued to this junction (33.1793182, -114.021716) with Wellton-Kofa Road. We took this south to another junction here (33.0636244, -113.958594) with Chain Tank Road. Wellton-Kofa Road cannot be accessed from the south since it's barred by a wilderness sign and also goes straight through Yuma Proving Grounds, despite what maps may say otherwise. Overall the roads were fine: King Road good for any vehicle, Wellton-Kofa Road needing some clearance and slower-moving due to a bunch of ins-and-outs of tiny drainages, and Chain Tank Road surpisingly no worse than Wellton-Kofa Road.

Keystone Tower seemed to be riddled by complex terrain on its south and southeast sides, so rather than spend time navigating all of that, we thought it made more sense to approach the peak from the southwest. We followed a wash until we could see the colorful cliffs lining the rim of our ridgeline traverse later in the day. First we wanted to get to Keystone Tower, the more exciting endeavor of the two peaks for the day. We chose a Class 2 gully with some light Class 3 toward its head for the ascent. There was some catclaw, boulder-hopping, and loose rock, but I enjoyed it enough to say its a decent route. On our descent later we used the saddle separating our two peaks, and that was more straightforward.

A lump to the south of Keystone Tower served as an excellent viewpoint toward the gorgeous hunk of volcanic rock we'd be attempting, despite being an obstacle adding vertical gain on the way back later. Class 2/3 brought us down to the base of Keystone Tower. We headed up the peak's mellow slope and wrapped around the eastern base with the hope to find some sort of weakness, since the west was clearly a sheer face. We were ignorantly confident there'd be a way up. We all separated, poking around at numerous options before settling on a route that somehow did indeed keep working out.

A Class 3 well-featured slab next to a crack led beneath a small cave from the ground, followed by some Class 3/3+ scrambling to a ledge with a small indentation in the volcanic rock. A Class 4 set of moves led from this indentation through a short chimney with a pull move at the top. From here Class 2/3 on very steep terrain took us up a combination of solid rock slabs and loose steppy ledges up to a wider walkable ledge higher up beneath an impassable headwall. We traversed to the right along this ledge and pulled a Class 4 lip move (not exposed). The ledge continued to a quite exposed Class 4 move on solid rock. Class 2 brought us up the subsequent slope and into an incut feature at the base of a headwall, which turned out to be the summit block. Wrapping around to its left, we almost circled the summit block entirely before Class 2+ got us up on the north side. We couldn't believe how excellent this route was, especially with how cryptic it seemed from below.

With enough time in the day, we all agreed we should head over to Peak 2740, despite our sore legs. The high point of the area, we figured we'd get some scenic views. We backtracked from Keystone Tower, passing over the lump we descended earlier, and then down to the saddle separating Keystone Tower and Peak 2740, some loose terrain on the way down. We'd use this saddle for our descent later. Ahead was the base of a serious-looking cliff, and after a steep slope ascent we side-hilled to the base of this cliff and wrapped around it on its left (south) side. Class 2 got us to the ridgeline above. A bit of navigating weaved us in and out of rock outcroppings and to flatter ground (Class 2/3).

We followed the colorful rim we'd noted from below earlier in the day, generally heading southwest. A couple of little lumps along the way and we were at the base of Peak 2740. A notch on its south side seemed like the best ascent option, so we hiked up the steep slope where we found the ridgeline to be a bit cliffy. Keeping to the left of the ridgeline initially, we decided to ascend as soon as the terrain became Class 2. Once along the ridgeline, we headed north to the high point. Nearby Castle Dome Peak and Thumb Peak were very cool viewed from this angle, especially with the complex terrain surrounding them.