From Tyler McMillen's Tucson Bouldering:
From the last parking lot at the terminus of the road past Summerhaven, take the Aspen trail up the hill. Follow the trail up the hill about 5 minutes, until it comes to the top of the first hill, and starts to flatten out. Continue long the trail for about thirty feet after it flattens out, then veer left off the trail, before the trail turns right and heads downhill. Veer down and left for about 50 yards, until you come to a big firepit, then cut down under the next boulder. This will bring you underneath the boulder's face. If you have trouble finding it, from where the trail flattens out, hike directly downhill to the rim of the canyon, and then turn right, then hike (bushwhack) along the rim, The boulder is on the rim, with the face facing downhill toward the river.
Featured Route For Mango Boulder