Most lakes in Michigan

Robert Brown Sanctuary

How lakes form

Kettle Wikipedia

Photo by Daniel Kerr.Photo courtesy of the Geological Survey of Canada, Canadian Government.

Kettle Lakes at Twin Lakes, SW of Houghton. Most lakes on the Keweenaw and most of Michigan are kettles.

http://www.landforms.eu/cairngorms/kettle%20hole.htm

During the glacial retreat, ice masses were broken and jumbled throughout the outwash and moraine which remained after the main ice lobe melted. That residual ice eventually melted and left a low spot, which filled with water, trapping a lake behind.  These lakes often have no outlet and are stabilized by groundwater, making them exquisitely pristine. We have excellent examples in the Keweenaw: Lake Annie,  Lake Perrault, Twin Lakes and many more. They are hallmarks of glacial history.

Kettle lakes formed from recent glacial retreat in Iceland (Google Earth and SPOT).