These lakes are all west of the Keweenaw Peninsula. To the east, the ice melt drained into Green Bay or Lake Michigan through channels crossing the western part of the upper peninsula of Michigan. Lake Duluth extended a few miles farther east than the Keweenaw Peninsula, to the border of the Huron Mountains, east of Keweenaw Bay. In the early part of the recession of the ice front Lake Duluth, with an outlet from the Brule River Valley through the St. Croix River Valley, was present in the western part of the Lake Superior Basin. A little later the ice border retreated sufficiently to allow the small independent lakes to become a part of Lake Duluth or to be drained by the lowering of the water level, for in general the water level was lowered as these lakes merged with Lake Duluth