Organ Pipe Cactus National Monument, Part 1: The Ajo Mountain Drive, Arch Canyon Trail, and Bull Pasture Trail
I spent four days at Organ Pipe Cactus National Monument in southern Arizona, amazed at what was a completely new landscape for me. The Sonoran Desert is famous for the saguaro cactus, which seem to dot the flats and hillsides everywhere west of Tuscon, but it’s only this far south that the organ pipe cactus – which migrated from Mexico only 4,500 years ago – shares space with it’s better-known cousin. The national monument thus preserves a unique ecosystem.
One of the most striking features of the monument other than the forests of cacti are the Ajo Mountains, which rise up to 3,000 feet over the alluvial basins. The mountains are primarily layers of tuff (ejected compressed volcanic ash) and rhyolite (type of solidified lava) which have been folded and tilted, creating amazing wave-like mountain faces, jagged cliffs, and other distortions. Although they can be seen from nearly anywhere within the park, the best views are from the 21-mile scenic Ajo Mountain Drive, which crosses low desert before winding up and through the mountains.
As fantastic as the sights from the drive are however, I cannot recommend enough parking at some of the trailheads (or any random spot) and going for a hike. I took numerous walks and hikes over the course of the day, but the standout was Bull Pasture Trail, a 4.5 mile hike that steeply ascends a wall of Estes Canyon and then travels along the ridge line, offering 360-degree views. This area of the mountains was also one of the lushest I saw in the park, and was strikingly green. I also did the 1.5 mile Arch Canyon Trail, a couple miles of the Historic Country Road Trail, and a few hundred feet climb up a random mountain that provided spectacular views.