Some of the earliest human inhabitants of the Lake Michigan region were the
Hopewell Indians. Their culture declined after 800 AD, and for the next few hundred years, the region was the home of peoples known as the
Late Woodland Indians. In the early 17th century, when western European explorers made their first forays into the region, they encountered descendants of the Late Woodland Indians: the
Potawatomi. The French explorer
Jean Nicolet is believed to have been the first European to reach Lake Michigan, possibly in 1634 or 1638.
 In the earliest European maps of the region, the name of Lake Illinois has been found in addition to that of "Michigan", named for the
Illinois Confederation of tribes.
Lake Michigan is joined via the narrow, open-water
Straits of Mackinac with Lake Huron, and the combined body of water is sometimes called Michigan–Huron (also Huron–Michigan). The Straits of Mackinac were an important
Native American and
fur trade route. Located on the southern side of the Straits is the town of
Mackinaw City, Michigan, the site of
Fort Michilimackinac, a reconstructed French fort founded in 1715, and on the northern side is
St. Ignace, Michigan, site of a
Catholic mission to the Indians, founded in 1671. In 1673,
Louis Joliet and their crew of five
voyageurs followed Lake Michigan to
Green Bay and up the Fox River, nearly to its headwaters, in their search for the Mississippi River, cf.
Fox–Wisconsin Waterway. The eastern end of the Straits was controlled by
Fort Mackinac on Mackinac Island, a British colonial and early American military base and fur trade center, founded in 1781.
With the advent of European exploration into the area in the late 17th century, Lake Michigan became part of a line of waterways leading from the
Saint Lawrence River to the
Mississippi River and thence to the
Gulf of Mexico.
coureurs des bois and voyageurs established small ports and trading communities, such as
Green Bay, on the lake during the late 17th and early 18th centuries.
In the 19th century, Lake Michigan played a major role in the development of
Chicago and the
Midwestern United States west of the lake. For example, 90% of the
grain shipped from Chicago traveled east over Lake Michigan during the
antebellum years, and only rarely falling below 50% after the
Civil War and the
major expansion of railroad shipping.
The first person to reach the deep bottom of Lake Michigan was
J. Val Klump, a scientist at the
University of Wisconsin–Milwaukee. Klump reached the bottom via
submersible as part of a 1985 research expedition.
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.