Lake Huron sits at the center of the Great Lakes system. It receives flow from Lake Superior via the St. Marys River and from Lake Michigan through the Straits of Mackinac — hydrologically, Huron and Michigan are a single lake at the same elevation. Outflow runs south through the St. Clair River to Lake St. Clair and on to Lake Erie. The total drainage basin covers about 51,700 square miles across Michigan and Ontario, with a water retention time of roughly 22 years — the fastest turnover of any Great Lake.
The open lake does not reliably freeze due to its depth (750 feet max) and enormous fetch. Protected bays and harbors in northern areas can develop ice, but conditions are highly variable and dangerous. Saginaw Bay in the southern portion is the major ice fishing destination. Never venture onto Great Lakes ice without current local reports and proper safety gear.