Lake Michigan

Lake Michigan is a massive body of fresh water in North America. It is one of the five Great Lakes. This lake is unique because it is the only Great Lake located entirely within the United States. The other four Great Lakes are shared between the U.S. and Canada.

The lake is bordered by four states: Wisconsin, Illinois, Indiana, and Michigan. Its name likely comes from the Ojibwe word "michi-gami," which means "great water." It is the largest lake in the world located completely within a single country.

The lake has a complex movement of water within its basin. An underwater feature called the Milwaukee Reef runs beneath the lake. This reef stretches from a point between Milwaukee and Racine to a point between Grand Haven and Muskegon. The reef divides the lake into two distinct areas: northern and southern basins. Each basin has a clockwise flow of water. This movement is driven by rivers and the wind. Prevailing westerly winds push surface water toward the east. This process has a moderating effect on the climate in western Michigan.

Lake Michigan is part of a much larger hydrological system. To the east, the Straits of Mackinac connect the lake to Lake Huron. Because of this connection, the two lakes share the same surface elevation. Hydrologically, they function as a single body of water known as Lake Michigan-Huron. Together, they form the largest freshwater body in the world by surface area. The Mackinac Bridge is often used as the dividing line between them. The main inflow from Lake Superior is controlled by locks operated by the bi-national Lake Superior Board of Control.

Many different cultures have a deep history with this region. The Hopewell Native Americans were among the earliest well-studied inhabitants. After their culture declined around 800 AD, the Late Woodland Native Americans lived in the area. In the early 17th century, European explorers arrived. Jean Nicolet is believed to be the first European to reach the lake, possibly in 1634 or 1638. He encountered many peoples, including the Ojibwe, Menominee, and Potawatomi. During the 1640s and 1650s, the Beaver Wars caused many people to move through the region.

The lake is massive in scale and depth. It has a surface area of approximately 22,300 square miles. This makes it the fifth-largest lake in the world. The average depth of the lake is 46 fathoms 3 feet, or 279 feet. Its deepest point is the Chippewa Basin, which reaches 153 fathoms 5 feet, or 923 feet. The lake contains a total volume of 1,183 cubic miles of water. In 1985, a scientist named J. Val Klump became the first person to reach the bottom. He used a research submersible to complete the expedition.

Human activity has always been tied to the lake's resources. In the 19th century, the lake was vital to the growth of Chicago and the Midwest. During the antebellum years, 90% of the grain shipped from Chicago traveled east over the lake. Even after railroads expanded, the volume rarely fell below 50% after the Civil War. Today, the lake provides drinking water to millions of people. Large lake freighters carry goods, though they must be different from ocean-going ships. Ocean-going container ships are often too large for the locks in the Saint Lawrence Seaway.

Water levels in the lake change throughout the year. Levels are typically highest in the summer and lowest in the winter. In October 1986, the lakes reached a high of 580.11 feet. However, levels can also drop significantly. In 2013, the lake reached an all-time low mean level of 576.53 feet. Experts say this was caused by a lack of snow in 2011 and 2012, along with hot, dry weather. The lake also contains many islands, mostly in the northern sections. Beaver Island is the largest island, while the Manitou Islands sit in Leelanau County.