Cabeza Prieta National Wildlife Refuge’s office and visitor center are in Ajo, Arizona. The coordinates to the Refuge’s visitor center are 32.385579, -112.872383. 

From Phoenix:

Take I-10 west to exit 112. Follow Highway 85 south to Gila Bend and continue south on 85 approximately 40 miles to Ajo. Watch for the brown sign with Cabeza Prieta National Wildlife Refuge on it. It will be on the west (right) side of the highway. 

From Tucson:

Take Highway 86 (Ajo Way) west across the Tohono O'odham reservation to the town of Why, turn right, and follow Highway 85 north to Ajo. Watch for the brown sign with Cabeza Prieta National Wildlife Refuge on it. It will be on the west (left) side of the highway. 

From Yuma:

Take I-8 east to Gila Bend and follow Highway 85 south approximately 40 miles to Ajo. Watch for the brown sign with Cabeza Prieta National Wildlife Refuge on it. It will be on the west (right) side of the highway.