The upper section of the river lies in a glaciated valley, with glacier scouring scars high up on the upper parts of the mountains of the West Coast Range. Also small glacial lakes occur on and north of Mount Sedgwick. Lake Beatrice for instance lies on the eastern slope of Mount Sedgwick. The upper portion of the King River valley was first surveyed for damming in 1917 by the Mount Lyell Mining and Railway Company.