Carbon Glacier Trail is in the n.w. corner of Mount Rainier National Park. A 17-mile trail leads hikers and bicyclists through virgin forests to Ipsut Creek Campground, which has limited hike-in camping facilities and access to back-country trails. A 3.5-mile trail leads hikers from the campground to Carbon Glacier, thought to be the lowest elevation reached by glacier ice in the 48 states. Campers must obtain a wilderness permit, available at ranger stations.Camping is permitted.