Sumdum Glacier starts on the south flank of Mount Sumdum with a summit elevation of 6,666 feet (2,032 m) and flows southwest to a hanging terminus at 2,100 feet (640 m) and the start of Powers Creek that flows 2 miles (3.2 km) to the eastern shore of Endicott Arm, about 89 miles (144 km) northeast of Sitka and 50 miles (81 km) southeast of Juneau, Alaska.