Lake Michigan is one of the five Great Lakes of North America. It is the second-largest Great Lake by volume, with 1,180 cubic miles (4,900 km³), and the second-largest by depth, at 923 feet (281 meters). It is the third-largest by surface area, covering 22,300 square miles (57,757 km²). To the east, Lake Michigan connects to Lake Huron through the wide and deep Straits of Mackinac. This connection means the two lakes share the same surface elevation and are considered one large lake, which is the largest freshwater lake in the world by area.

Lake Michigan is the only Great Lake entirely within the United States. The other four Great Lakes are shared between the United States and Canada. Lake Michigan is located in the U.S. states of Wisconsin, Illinois, Indiana, and Michigan. Major ports along its shore include Chicago, Illinois; Gary, Indiana; Milwaukee and Green Bay, Wisconsin; and Muskegon, Michigan. To the north, the lake has long bays, such as Green Bay in the northwest and Grand Traverse and Little Traverse bays in the northeast. The name "Michigan" is believed to come from the Ojibwe word michi-gami or mishigami, meaning "great water."

History

Some of the earliest human groups studied in the Lake Michigan area were the Hopewell Native Americans. Their culture ended around 800 AD, and for the next few hundred years, the region was home to people called the Late Woodland Native Americans. In the early 1600s, when European explorers first arrived, they met descendants of the Late Woodland Native Americans, including the Ojibwe, Menominee, Noquet, Sauk, Meskwaki, Ho-Chunk, Miami, Odawa, and Potawatomi peoples. The French explorer Jean Nicolet is thought to have been the first European to reach Lake Michigan, possibly in 1634 or 1638. Early European maps of the region included the name "Lake Illinois," which honored the Illinois Confederation of tribes, as well as "Michigan." During the 1640s and 1650s, the Beaver Wars (a conflict over the fur trade) began with the Iroquois, causing many people in the region to flee. These people sought safety to the west and north of Lake Michigan.

The Straits of Mackinac were an important path for Native American travel and fur trading. On the southern side of the straits is the town of Mackinaw City, Michigan, where Fort Michilimackinac (a rebuilt French fort built in 1715) is located. On the northern side is St. Ignace, Michigan, where a French Catholic mission to Native Americans was established in 1671. In 1673, Jacques Marquette, Louis Jolliet, and their crew of five Métis voyageurs traveled along Lake Michigan to Green Bay and up the Fox River, nearly to its source, in search of the Mississippi River. By the late 1700s, the eastern parts of the straits were controlled by Fort Mackinac on Mackinac Island, a British and early American military base and fur trade center built in 1781.

When Europeans began exploring the area in the late 1600s, Lake Michigan became part of a network of waterways connecting the Saint Lawrence River to the Mississippi River and the Gulf of Mexico. French coureurs des bois and voyageurs created small ports and trading communities, such as Green Bay, on the lake during the late 1600s and early 1700s. In the 1800s, Lake Michigan played a key role in the growth of Chicago and the Midwestern United States west of the lake. For example, 90% of the grain sent from Chicago traveled by ship east over Lake Michigan during the years before the Civil War. Even after the Civil War, this shipping remained strong, with the volume rarely dropping below 50% despite the expansion of railroads.

In 1985, J. Val Klump, a scientist from the University of Wisconsin–Milwaukee, became the first person to reach the deep bottom of Lake Michigan. He used a submersible during a research expedition. A 2018 report by Purdue University studied the warming of Lake Michigan. Surface temperatures have risen steadily each decade since 1980. This warming may harm native habitats and make it harder for native species, including game fish, to survive.

Hydrology

Lake Michigan runs under Lake Michigan from a point between Milwaukee and Racine to a point between Grand Haven and Muskegon. This underwater ridge splits the lake into two parts: a northern basin and a southern basin. Water in both basins moves in a clockwise direction, driven by rivers and wind. Strong winds from the west push surface water toward the east, helping to keep the climate of western Michigan milder. In summer, the water near the Wisconsin and Michigan shores can differ in temperature by 5 to 10 degrees Fahrenheit (2 to 5 degrees Celsius).

Lake Michigan and Lake Huron are connected and are sometimes called Lake Michigan-Huron. Together, they form the largest fresh water area in the world. The Mackinac Bridge marks the boundary between the two lakes. Water from Lake Superior flows into Lake Michigan through Lake Huron, controlled by locks managed by a group from the United States and Canada.

Lake Michigan is the only Great Lake entirely within the United States. The other Great Lakes share borders with Canada. Lake Michigan covers 22,404 square miles (58,030 square kilometers), with parts in Michigan, Wisconsin, Indiana, and Illinois. It is the largest lake fully within one country by surface area, though Lake Baikal in Russia holds more water by volume. Lake Michigan is also the larger half of Lake Michigan-Huron, which is the largest fresh water area in the world. It is 307 miles (494 kilometers) long, 118 miles (190 kilometers) wide, and has a shoreline 1,640 miles (2,640 kilometers) long. The lake averages 46 fathoms 3 feet (279 feet; 85 meters) in depth, with its deepest point at 153 fathoms 5 feet (923 feet; 281 meters). It holds 1,183 cubic miles (4,932 cubic kilometers) of water. Green Bay in the northwest is the largest bay, and Grand Traverse Bay in the northeast is another large bay. The deepest part of the lake, called the Chippewa Basin, is in the northern half and is separated from the South Chippewa Basin by a shallower area called the Mid Lake Plateau.

Beaver Island, at 55.8 miles (145 kilometers) long, is the largest island in Lake Michigan. It is part of an island group in Charlevoix County, Michigan, which includes Garden Island, Grape Island, Gull Island, Hat Island, High Island, Hog Island, Horseshoe Island, Little Island, Pismire Island, Shoe Island, Ojibwa Island, Trout Island, and Whiskey Island. Fisherman’s Island is also in Charlevoix County. Other island groups include the Fox Islands (North Fox Island and South Fox Island) in Leelanau County, the Manitou Islands (North Manitou Island and South Manitou Island) in Leelanau County, and islands in Grand Traverse Bay such as Bassett Island, Bellow Island, and Power Island. Islands south of the Garden Peninsula in Delta County include Gravelly Island, Gull Island, Little Gull Island, Little Summer Island, Poverty Island, Rocky Island, St. Martin Island, and Summer Island. Islands in Big Bay de Noc include Round Island, St. Vital Island, and Snake Island. Islands in Little Bay de Noc include Butlers Island and Sand Island. Wilderness State Park in Emmet County contains Temperance Island and Waugoshance Island. Ile Aux Galets is also in Emmet County. In Mackinac County, Epoufette Island, Gravel Island, Little Hog Island, and Naubinway Island are found. Green Island and St. Helena Island are near the Mackinac Bridge. Islands around the Door Peninsula in Wisconsin include Chambers Island, Fish Island, Gravel Island, Spider Island, Horseshoe Island, the Sister Islands, Detroit Island, Green Island, Hog Island, Pilot Island, Plum Island, Rock Island, the Strawberry Islands, and Washington Island. The northern half of the peninsula is technically an island due to the Sturgeon Bay Ship Canal. Northerly Island, a man-made peninsula in Chicago, is home to the Adler Planetarium, the former Meigs Field, and the Huntington Bank Pavilion.

In the mid-20th century, the Saint Lawrence Seaway and Great Lakes Waterway were built, allowing large ships to travel through the Great Lakes. However, newer, larger container ships cannot fit through the locks, limiting shipping on the lakes. Lake freighters are used for transporting goods on the lakes. Despite their size, large parts of the Great Lakes freeze in winter, stopping most shipping. Some icebreakers help ships move through the ice.

Lake Michigan connects to the Gulf of Mexico via the Illinois Waterway, Illinois River, and Mississippi River. Commercial tug-and-barge traffic on these waterways is heavy. Pleasure boats can enter or leave the Great Lakes through the Erie Canal and Hudson River in New York. The Erie Canal connects to the Great Lakes at the east end of Lake Erie (Buffalo, New York) and the south side of Lake Ontario (Oswego, New York).

Lake Michigan’s water levels change monthly, with the highest levels usually in summer. The normal high-water mark is 2.00 feet (60 cm) above a reference point (577.5 ft or 180 m). In October 1986, Lakes Michigan and Huron reached their highest level at 5.92 feet (1.80 m) above the reference point. In 2020, monthly high-water records were broken for several months in a row.

Lake levels are lowest in winter. The normal low-water mark is 1.00 foot (30 cm) below the reference point (577.5 ft or 176.0 m). In the winter of 1964, Lakes Michigan and Huron reached their lowest level at 1.38 feet (42 cm) below the reference point. From February 1964 to January 1965, monthly low-water records were set. The all-time low-water mark was reached in January 2013. In January 2013, Lake Michigan’s water levels dropped to 576.2 ft (175.6 m), the lowest since record-keeping began in 1918. Water levels were 29 inches (74 cm) below the long-term average and 17 inches (43 cm) lower than in January 2012. Officials said the main causes were a lack of snow

Shoreline

Lake Michigan has many beaches. This area is sometimes called the "Third Coast" of the United States, following the coasts of the Atlantic Ocean and the Pacific Ocean. The sand on the beaches is often soft and light-colored, called "singing sands" because it makes a squeaking sound when walked on. This sound happens because the sand contains a lot of quartz. Some beaches have sand dunes covered with green beach grass and sand cherries. The water is usually clear and cool, with temperatures between 55 and 80 °F (13 and 27 °C), even in late summer. However, winds that blow from the west move surface water toward the east, bringing warmer water to the Michigan shore during the summer.

The largest freshwater sand dune system in the world is found on the east shore of Lake Michigan. In many places along the shoreline, dunes rise hundreds of feet above the lake. Large dune formations can be seen in state parks, national forests, and national parks along the Indiana and Michigan coasts. Some of the most famous dunes are located in Indiana Dunes National Park, Saugatuck Dunes State Park, Warren Dunes State Park, Hoffmaster State Park, Silver Lake State Park, Ludington State Park, and Sleeping Bear Dunes National Lakeshore. Smaller dunes are found on the western shore at Illinois Beach State Park, and moderate-sized dunes are found in Kohler-Andrae State Park and Point Beach State Forest in Wisconsin. A large dune is located in Whitefish Dunes State Park on Wisconsin’s Door Peninsula. Petoskey stones, the official state stone of Michigan, can be found on Lake Michigan beaches in Northern Michigan, as well as in a few inland lakes in the region.

The western and northernmost parts of the eastern coast often have rocky beaches, while the southern and eastern beaches are usually sandy and covered with dunes. This happens partly because winds from the west push ice onto the eastern shore in winter. The Chicago waterfront has been developed for parks, beaches, harbors, marinas, and homes, connected by the Chicago Lakefront Trail. In areas without beaches or marinas, stone or concrete barriers protect the shoreline from erosion. The Chicago lakefront is accessible for about 24 miles (39 km) between the city’s southern and northern limits along the lake.

Twelve million people live along Lake Michigan’s shores, mostly in the Chicago and Milwaukee metropolitan areas. Tourism supports the economy of many communities in northern Michigan and Door County, Wisconsin, with large seasonal populations visiting the area. Many seasonal residents own summer homes along the lake and return to other homes during the winter. The southern end of the lake near Gary, Indiana, is heavily industrialized.

Cities along Lake Michigan include:

• Chicago
• Evanston
• Wilmette
• Winnetka
• Kenilworth
• Glencoe
• Highland Park
• Lake Forest
• Lake Bluff
• Naval Station Great Lakes
• North Chicago
• Waukegan
• Beach Park
• Zion
• Winthrop Harbor

• East Chicago
• Gary
• Hammond
• Michigan City
• Portage
• Porter
• Whiting

• Benton Harbor
• Bridgman
• Charlevoix
• Douglas
• Elberta
• Escanaba
• Ferrysburg
• Frankfort
• Gladstone
• Glenn
• Grand Beach
• Grand Haven
• Harbor Springs
• Ludington
• Manistee
• Manistique
• Menominee
• Michiana
• Muskegon
• New Buffalo
• Norton Shores
• Pentwater
• Petoskey
• Saugatuck
• St. Joseph
• Shoreham
• South Haven
• Traverse City

• Algoma
• Bay View
• Cudahy
• Fox Point
• Green Bay
• Kenosha
• Kewaunee
• Manitowoc
• Marinette
• Milwaukee
• Mequon
• Oconto
• Port Washington
• Racine
• Saint Francis
• Sheboygan
• Shorewood
• South Milwaukee
• Sturgeon Bay
• Two Rivers
• Whitefish Bay
• Waterford

The National Park Service manages Sleeping Bear Dunes National Lakeshore and Indiana Dunes National Park. Parts of the shoreline are in Hiawatha National Forest and Manistee National Forest. The Manistee National Forest includes the Nordhouse Dunes Wilderness. The Lake Michigan division of the Michigan Islands National Wildlife Refuge is also in the lake, along with the Green Bay National Wildlife Refuge and the Wisconsin Shipwreck Coast National Marine Sanctuary.

Many state and local parks are located along Lake Michigan’s shores or on islands in the lake.

Human activities

Lake Michigan is home to a small number of fish and other living things. Originally, the lake had species like lake whitefish, lake trout, yellow perch, walleye, largemouth bass, smallmouth bass, bowfin, and some types of catfish. However, after improvements to the Welland Canal in 1918 and the arrival of sea lampreys, along with overharvesting, native lake trout populations decreased. This led to an increase in the population of alewife, an invasive species. To control the alewife population, salmonids, such as brown trout, steelhead (rainbow trout), coho salmon, and chinook salmon, were introduced as predators. This effort was very successful, leading to a large increase in the numbers of these introduced fish. Today, Lake Michigan is stocked yearly with steelhead, brown trout, and coho and chinook salmon, which have also started to reproduce naturally in some of the lake’s tributaries. However, invasive species like lampreys, round goby, zebra mussels, and quagga mussels continue to affect water clarity and fertility, causing changes in the lake’s ecosystem and threatening native fish populations.

Fisheries in inland U.S. waters are smaller compared to marine fisheries. The largest fisheries are from the Great Lakes, which were worth about $14 million in 2001. Today, Michigan’s commercial fishery is mainly operated by 150 tribe-licensed fishing operations through the Chippewa-Ottawa Resource Authority and tribes in the Great Lakes Indian Fish and Wildlife Commission. These groups harvest about half of the Great Lakes’ commercial catch in Michigan waters. There are also 45 state-licensed commercial fishing businesses. The main commercial fish species is the lake whitefish. The annual harvest of lake whitefish dropped from an average of 11 million pounds (5,000 tons) between 1981 and 1999 to 8 to 9.5 million pounds (3,600 to 4,300 tons) in recent years. The price of lake whitefish also decreased from $1.04 per pound to as low as $0.40 per pound during times of high production.

Sports fishing in Lake Michigan includes catching salmon, whitefish, smelt, lake trout, and walleye. In the late 1960s, successful stocking programs for Pacific salmon helped develop Lake Michigan’s charter fishing industry.

Like all the Great Lakes, Lake Michigan is used for transporting bulk goods. In 2002, 162 million net tons of dry bulk cargo were moved through the lakes. The largest types of cargo were iron ore, grain, and potash. Iron ore, along with much of the stone and coal, is used in the steel industry. Some liquid and containerized cargo is also shipped, but most container ships cannot pass through the locks on the Saint Lawrence Seaway because they are too wide. The amount of shipping on the Great Lakes has been decreasing over the years. The Port of Chicago, managed by the Illinois International Port District, has storage facilities for grain (14 million bushels) and bulk liquids (800,000 barrels) along Lake Calumet. Calumet Harbor, a central part of the Port District, is maintained by the U.S. Army Corps of Engineers.

Two passenger and vehicle ferries operate across Lake Michigan, connecting Wisconsin on the western shore with Michigan on the east. From May to October, the historic steamship SS Badger runs daily between Manitowoc, Wisconsin, and Ludington, Michigan, linking U.S. Highway 10 between the two cities. The Lake Express, which began service in 2004, carries passengers and vehicles between Milwaukee, Wisconsin, and Muskegon, Michigan.

Tourism and recreation are important industries on the Great Lakes. A few small cruise ships operate on Lake Michigan, including some sailing ships. Many water sports are practiced on the lakes, such as yachting, sea kayaking, diving, kitesurfing, and lake surfing. Passenger steamers have been operating on the Great Lakes since the mid-19th century. Several ferries currently run on the Great Lakes to take passengers to islands like Beaver Island and Bois Blanc Island (Michigan). From around April to November, two car ferry services operate on Lake Michigan: the SS Badger, a steamer between Ludington, Michigan, and Manitowoc, Wisconsin, and the Lake Express, a high-speed catamaran between Milwaukee, Wisconsin, and Muskegon, Michigan.

The Great Lakes Circle Tour is a scenic road system that connects all the Great Lakes and the St. Lawrence River. Lake Michigan is also a place where people can see ice volcanoes, which usually form at the start of winter.