Lake Huron is one of the five Great Lakes of North America. Hydrologically, it comprises the easterly portion of Lake Michigan–Huron, having the same surface elevation as its westerly counterpart, to which it is connected by the 5-mile-wide (8.0 km), 20-fathom-deep (120 ft; 37 m) Straits of Mackinac. It is shared on the north and east by the Canadian province of Ontario and on the south and west by the U.S. state of Michigan. The name of the lake is derived from early French explorers who named it for the Huron people inhabiting the region.The Huronian glaciation was named from evidence collected from Lake Huron region. The northern parts of the lake include the North Channel and Georgian Bay. Saginaw Bay is located in the southwest corner of the lake. The main inlet is the St. Marys River, and the main outlet is the St. Clair River.
Lake Huron has a lake retention time of 22 years. Like all of the Great Lakes, the ecology of Lake Huron has undergone drastic changes in the last century. The lake originally supported a native deepwater fish community dominated by lake trout, which fed on several species of ciscos as well as sculpins and other native fishes. Several invasive species, including sea lamprey, alewife and rainbow smelt, became abundant in the lake by the 1930s. The major native top predator, lake trout, was virtually extirpated from the lake by 1950 through a combination of overfishing and the effects of sea lamprey. Several species of ciscos were also extirpated from the lake by the 1960s; the only remaining native cisco is the bloater. Non-native Pacific salmon have been stocked in the lake since the 1960s, and lake trout have also been stocked in an attempt to rehabilitate the species, although little natural reproduction of stocked trout has been observed.
Lake Huron has suffered recently by the introduction of a variety of new invasive species, including zebra and quagga mussels, the spiny water flea, and round gobies. The demersal fish community of the lake was in a state of collapse by 2006, and a number of drastic changes have been observed in the zooplankton community of the lake. Chinook salmon catches have also been greatly reduced in recent years, and lake whitefish have become less abundant and are in poor condition. These recent changes may be attributable to the new exotic species.