The NOAA website contains links to raw data in various formats as well as completed maps of Great Lakes bathymetry. There are also some bathymetric charts of the Great Lakes available physically at the Clark Library.
The Michigan Department of Natural Resources has maps of over 2000 inland lakes in the state of Michigan. Physical copies of some of these maps are available at the Clark Library, including ones that may not be covered by Michigan DNR. Please contact email@example.com if you require use of these maps.