Carbon Glacier is located on the north slope of Mount Rainier in the U.S. state of Washington and is the source of the Carbon River. The snout at the glacier terminal moraine is at about 3,500 feet (1,100 m) above sea level, making it the lowest-elevation glacier in the contiguous United States. The glacier also has the greatest length (5.7 miles (9.2 km)), thickness (700 ft (210 m)) and volume (0.2 cubic miles (0.83 km3)) of any U.S.