Lake Minong was a proglacial lake that formed in the Lake Superior basin during the Wisconsin glaciation around 10,000 B.P. This was the last glacial advance that entered Michigan and covered only part of the upper peninsula. Lake Minong occurred in the eastern corner of the Lake Superior basin while Lake Duluth was in the western end. The lakes became separated when the glacier reached the upper peninsula. Lake Minong expanded to the north as the ice retreated after 9,800 B.P. When the ice retreated from the Keweenaw Peninsula, Lake Duluth merged into Lake Minong.