Stages of great lake development.
Early Lake Erie was a prehistoric proglacial lake that existed at the end of the last ice age approximately 13,000 years ago. The early Erie fed waters to Glacial Lake Iroquois.
Then ancient lake was similar in size to the current lake during glacial retreat, but some period the western half of the lake was covered with ice.
Early-period Lake Erie was made up of smaller lakes (Lakes Warren, Wayne, Maumee and Lundy) with lower depths. Much of the ancient lake bed is now northern Ohio.