Great Lakes Compact Great Lakes Compact The Great Lakes–St. Lawrence River Basin Water Resources Compact is a legally binding interstate compact among the U.S. states of Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania and Wisconsin. The compact details how the states manage the use of the Great Lakes Basin's water supply and builds on the 1985 Great Lakes Charter and its 2001 Annex. The compact is the means by which the states implement the governors' commitments under the Great Lakes–St. Lawrence River Basin Sustainable Water Resources Agreement that also includes the Premiers of Ontario and Quebec. The Council of Great Lakes Governors,
Great Lakes for Lakes Ontario and Erie were created, along with what would become the Saint Lawrence River. The Great Lakes are estimated to have been formed at the end of the last glacial period (the Wisconsin glaciation ended 10,000 to 12,000 years ago), when the Laurentide Ice Sheet receded. The retreat of the ice sheet left behind a large amount of meltwater (see Lake Algonquin, Lake Chicago, Glacial Lake Iroquois, and Champlain Sea) that filled up the basins that the glaciers had carved, thus creating the Great Lakes as we know them today. Because of the uneven nature of glacier erosion,