Gro Benchmark is the highest point in the Growler Mountains. These remote mountains rise above the desert plains just west of Organ Pipe Cactus National Monument. The Growlers are located in the Cabeza Prieta National Wildlife Refuge.
Few people ever climb Gro Benchmark. A check of Peakbagger.com reveals only six registered ascents as of March 2018. But for those willing to venture off into the desert wilderness, an ascent of Gro Benchmark makes for a worthy objective.
From Hwy 85 just south of Ajo, turn onto Darby Wells Road. Zero your odometer here. At 1.9 miles, stay left on the now Bates Well Road. At 9.5 miles, go right. At 10.5 miles, go right. At 11.9 miles, go right. You are now just northeast of Lime Hill. At 13.0 miles, you will reach the Cabeza Prieta National Wildlife Refuge boundary south of Camerons Tank. Recreational vehicles are “officially” prohibited from traveling any further. If you park here, it will be a long walk. If you decide to continue on, turn left at 13.1 miles onto a road not shown on the topo map. The road ends at 15.0 miles. The last few miles of the road are rough.
See the attached GPS track. If you start from the end of the road, the hiking distance is around 4.75 miles, with about 1,800’ of total gain. There is some rock scrambling around 2,500’ where the ridge narrows. Otherwise, this is a Class 1 and 2 hike across moderate terrain.