Harquahala Mountains
The very windy summit can be reached via a rough, 4-wheel drive road. This high point was used by the U.S. Army in the 1880s as a heliograph station. Then in 1920 a Smithsonian Astrophysical Observatory was constructed on this summit and operated for five years before being relocated to Table Mountain Observatory, near Wrightwood, California. Its purpose was to study variations in the solar output as a possible factor in climate prediction.
Designated in 1990, the 22,880-acre (93 km) the Harquahala Mountain Wilderness lies to the north and east of the summit at 33°49′40″N 113°17′52″W / 33.82778°N 113.29778°W on the Maricopa / La Paz county line.
At the southwest end of the mountain range, there are gypsum mines and in the past there were extensive mines for gold and silver.