Geology
Lake Huron has the largest shore line length of any of the Great Lakes, counting its 30,000 islands.
Lake Huron is separated from Lake Michigan, which lies at the same level, by the narrow Straits of Mackinac, making them geologically and hydrologically the same body of water (sometimes called Lake Michigan-Huron and sometimes described as two 'lobes of the same lake'). Aggregated, Lake Huron-Michigan, at 45,300 square miles (117,000 km2), "is technically the world's largest freshwater lake." When counted separately, Lake Superior is slightly larger than both; and higher. Lake Superior drains into the St. Marys River at Sault Ste. Marie which then flows southward into Lake Huron. The water then flows south to the St. Clair River, at Port Huron, Michigan and Sarnia, Ontario.
The Great Lakes Waterway continues thence to Lake St. Clair; the Detroit River and Detroit, Michigan; into Lake Erie and thence – via Lake Ontario and the St. Lawrence River – to the Atlantic Ocean.
Like the other Great Lakes, it was formed by melting ice as the continental glaciers retreated toward the end of the last ice age. Before this, Lake Huron was a low-lying depression through which flowed the now-buried Laurentian and Huronian Rivers; the lake bed was criss-crossed by a large network of tributaries to these ancient waterways, with many of the old channels still evident on bathymetric maps.
Read more about this topic: Lake Huron