Geologic History of the Lower St. Louis River

The lower St. Louis River was shaped by ancient bedrock and powerful glacial forces. As glaciers retreated over 10,000 years ago, meltwater carved channels and deposited red clay, sand, and silt from Glacial Lake Duluth. Land rebound and shifting waters later formed today’s freshwater estuary, sheltered from Lake Superior by a baymouth sand bar. Learn more about the Geologic history here!