<P> In 2007, a row of stones paralleling an ancient shoreline was discovered by Mark Holley, professor of underwater archeology at Northwestern Michigan College . This formation lies 40 feet (12 m) below the surface of the lake . One of the stones is said to have a carving resembling a mastodon . So far the formation has not been authenticated . </P> <P> Lake Michigan is the only one of the Great Lakes wholly within the borders of the United States; the others are shared with Canada . It lies in the region known as the American Midwest . </P> <P> Lake Michigan has a surface area of 22,404 sq. mi (58,026 km); (13,237 square miles, 34,284 km lying in Michigan state, 7,358 square miles, 19,056 km in Wisconsin, 234 square miles, 606 km in Indiana, & 1,576 square miles, 4,079 km in Illinois) making it the largest lake entirely within one country by surface area (Lake Baikal, in Russia, is larger by water volume), and the fifth - largest lake in the world . It is the larger half of Lake Michigan--Huron, which is the largest body of fresh water in the world by surface area . It is 307 miles (494 km) long by 118 miles (190 km) wide with a shoreline 1,640 miles (2,640 km) long . The lake's average depth is 46 fathoms 3 feet (279 ft; 85 m), while its greatest depth is 153 fathoms 5 feet (923 ft; 281 m). It contains a volume of 1,180 cubic miles (4,918 km3) of water . Green Bay in the northwest is its largest bay . Grand Traverse Bay in its northeast is another large bay . Its deepest region, which lies in its northern - half, is called Chippewa Basin (named after prehistoric Lake Chippewa) and is separated from South Chippewa Basin, by a relatively shallower area called the Mid Lake Plateau . </P> <P> Twelve million people live along Lake Michigan's shores, mainly in the Chicago and Milwaukee metropolitan areas . The economy of many communities in northern Michigan and Door County, Wisconsin is supported by tourism, with large seasonal populations attracted by the beauty and recreational opportunities offered by Lake Michigan . Seasonal residents often have summer homes along the waterfront and return home for the winter . The southern tip of the lake near Gary, Indiana is heavily industrialized . Cities on the shores of Lake Michigan include: </P>

How wide is lake michigan at its widest point