Kettle hole is a bowl-shaped hollow in the loose rocks and other material that have been deposited by a melting glacier. As a glacier retreats, large blocks of ice that have separated from it are left behind. These blocks of ice may then be wholly or partially buried in material deposited by the melting glacier. When such a block of ice melts, it leaves a kettle hole. Some shallow kettle holes remain dry. However, many kettle holes fill with water and form swamps or kettle lakes. Nearly all the shallow lakes in Michigan, Minnesota, and Wisconsin occupy kettle holes.
