Lake McDonald is the largest lake in Glacier National Park, Montana. It is approximately 10 miles long, and over a mile wide and 472 feet deep, filling a valley formed by a combination of erosion and glacial activity. Lake McDonald lies at an altitude of 3,153 feet and is on the west side of the Continental Divide. The Going-to-the-Sun Road parallels the lake along its southern shoreline from whence we took this photo. The surface area of the lake is 6,823 acres.