Branching off East Tanque Verde Road, the Sky Island Scenic Byway (a.k.a. Catalina Highway) starts at the desert floor in ocotillo, prickly pear, and saguaro and climbs to almost 9,157 feet. Mt Lemmon is the centerpiece of the massive Catalina Mountain Range. To reach the top of the Byway, visitors will cross a hidden fault at the base of the mountain range and then pass by bands of dark and light gray Catalina Gneiss exposed in roadcuts and natural outcrops.