Lake Michigan connects to Lake Huron through the Straits of Mackinac — together they form a single hydrological system at the same surface elevation, making Lake Michigan-Huron the world's largest freshwater lake by area. Major Michigan-side tributaries include the Grand River, Muskegon River, Kalamazoo River, St. Joseph River, Manistee River, and Boardman River (which flows through Traverse City into West Grand Traverse Bay). On the southern end, engineered channels connect to the Illinois River system via the Chicago Sanitary and Ship Canal.
The open waters of Lake Michigan do not freeze over reliably — the lake's 923-foot depth and massive volume prevent full ice cover in most winters. However, the more protected Grand Traverse Bays can develop fishable ice in cold winters, supporting whitefish and perch fishing. Bay ice is highly variable year to year; always verify conditions locally and never venture onto Great Lakes ice without current, trusted reports.