This guide is based on a Sage article by Mark Adrian.
Topo Map: Gladden 15
Trip Stats: 4 mi. on trail, Class 1
From Quartzsite. AZ, head E on I10 and take exit 31 onto AZ 60 to Brenda, AZ. Proceed E on AZ 60 through the town of Wendon to mile past 70. Then, continue another 0.5 miles to where there is a roadside rest area on the N side of AZ 6O. Directly across the highway on its S side, there is a closed barbed-wire fence/gate. Go through the gate, make an immediate "S" bend and continue 2.2 miles to the Wilderness boundary keeping left at all forks. The road is poor dirt, but is accessible to careful 2WDs. There is parking for at least six vehicles at the trailhead. marked by several BLM "brown stake" wilderness "posts".
Beginning as an old road bed, the four mile, class one trail, starts here, just beyond the posts, and heads SE. The path is well ducked for most of its route as it proceeds up the canyon. The sides of the canyon are rich in desert vegetation, with magnificent stands of saguaro being the most dramatic. During the second mile or so: remains of an old telephone line call been seen strung between boulders -- part of the old Observatory's installation.
As the canyon narrows, the trail climbs upwards and transitions into a series of switchbacks, passing a spring near 4200 feet. There's plenty of over-growth and virulent catclaw along the way, especially in these last two miles. At times, the path can be hard to follow through the thick foliage. Eventually, the route tops out at a saddle. With good views all around. From this windy vantage point, the dormant Observatory can be seen as a landmark. The trail turns E here, and ascends an easy ridge line to connect with a service road to the summit.
The highest point in southwestern Arizona, this peak straddles the western edge of the 22,880-acre Harquahala Mountains Wilderness which was established via the Arizona Desert Wilderness Act of 1990. Although a rugged 10.5 mile 4WD road skirts the Wilderness boundary to the summit, we chose to take the scenic and historic trail, contained entirely within the Wilderness area.
The four mile trail to the summit was created in 1920 and used by mules to haul supplies and materials to the then active Harquahala Peak Observatory, Constructed by, the Smithsonian Astrophysical Observatory and first operated by Dr. Charles G. Abbot. The facility was active from 1920 to 1925. The Observatory was commissioned to study and research the "solar constant". which aided weather forecasting. The facility closed in 1925 due to extreme weather conditions and decreased visibility. In 1975 the site was listed on the National Register of Historic Places. There is much more to the history of the Observatory than space permits here. The single remaining shack there is well fenced and embellished with a BLM info-placard and visitor's register. In addition to these relics, there is a large, solar-powered, microwave communications facility, that is operated by the Central Arizona Water Control District to control water flow in the Central Arizona Project canals.