The eastern limits of Lake Duluth on the south shore have been found to be at the Huron Mountains, in Marquette County, Michigan. Once the ice receded to the east of the mountains, new outlets opened across the Upper Peninsula of Michigan, carrying the melt water into the Lake Michigan basin. Lake Duluth was lowered as lower lines drainage along the ice front. Eventually the water level reached that of Lake Algonquin. The body of water occupied the western part of the Lake Superior basin as well as the basins of Lake Michigan and Lake Huron and finally the eastern part of the Lake Superior basin.