Natural Wonders
About Lake McDonald
The geology, clarity and ancient history behind Glacier's largest lake
More Than a Pretty Lake
Lake McDonald is the largest lake in Glacier National Park — 10 miles long, 1.5 miles wide, and 472 feet deep at its lowest point. Carved by glacial forces over 12,000 years ago, it holds water so clear you can see the bottom from a kayak in summer, lined with smooth pebbles in a palette of red, green, purple and teal that visitors mistake for painted stones the first time they see them.
The guides below explore the science behind what makes this lake visually unlike anything else in North America. No filters, no art direction — just a very old, very cold, very protected lake doing exactly what it has always done.