Porcupine Rim Trail, in the Sand Flats Recreation Area near Moab, Utah, is a prominent mountain biking route often associated with the Slickrock Trail. Riders usually take it as a 14.4-mile one-way descent with shuttle support, though it can also be ridden as a 30.8-mile loop. After an initial 4-mile climb of about 900 feet over rocky, sandy, and slickrock terrain, the route reaches an overlook before descending about 2,800 feet over 11 miles toward the Colorado River. Known for technical riding, repeated drops, and exposed sections, it ends at Highway 128 near Grandstaff Canyon, with motorized use closed beyond a junction 8.6 miles from the trailhead.