Illinois Waterway in the context of "Great Lakes Waterway"

The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes spanning the Canada–United States border. The five lakes are Superior, Michigan, Huron, Erie, and Ontario (though hydrologically, Michigan and Huron are a single body of water, joined at the Straits of Mackinac). The Great Lakes Waterway enables modern travel and shipping by water among the lakes. The lakes connect ultimately to the Atlantic Ocean via the Saint Lawrence River as their primary drainage outflow. The lakes are also connected to the Mississippi River basin through the Illinois Waterway.

The Great Lakes are the largest group of freshwater lakes on Earth by total area and the second-largest by total volume. They contain 21% of the world's surface fresh water by volume. The total surface is 94,250 square miles (244,106 km), and the total volume (measured at the low water datum) is 5,439 cubic miles (22,671 km), slightly less than the volume of Lake Baikal (5,666 cu mi or 23,615 km, 22–23% of the world's surface fresh water). Because of their sea-like characteristics, such as rolling waves, sustained winds, strong currents, great depths, and distant horizons, the five Great Lakes have long been called inland seas. Depending on how it is measured, by surface area, either Lake Superior or Lake Michigan–Huron is the second-largest lake in the world and the largest freshwater lake. Lake Michigan is the largest lake, by surface area, that is entirely within one country, the United States.

The Illinois River (Miami-Illinois: Inoka Siipiiwi) is a principal tributary of the Mississippi River at approximately 273 miles (439 km) in length. Located in the U.S. state of Illinois, the river has a drainage basin of 28,756.6 square miles (74,479 km). The Illinois River begins with the confluence of the Des Plaines and Kankakee rivers in the Chicago metropolitan area, and it generally flows to the southwest across Illinois, until it empties into the Mississippi near Grafton, Illinois. Its drainage basin extends into southeastern Wisconsin, northwestern Indiana, and a very small area of southwestern Michigan in addition to central Illinois. Along its banks are several river ports, including the largest, Peoria, Illinois. Historic and recreation areas on the river include Starved Rock, and the internationally important wetlands of the Emiquon Complex and Dixon Waterfowl Refuge.

The river was important among Native Americans and French traders as the principal water route connecting the Great Lakes with the Mississippi. The French colonial settlements along these rivers formed the heart of the area known as the Illinois Country in the 17th and 18th centuries. After the construction of the Illinois and Michigan Canal and the Hennepin Canal in the 19th century, the role of the river as link between Lake Michigan and the Mississippi was extended into the era of modern industrial shipping. The Illinois now forms the basis for the Illinois Waterway, extending the river's capabilities for navigation and commercial shipping.

The Illinois and Michigan Canal connected the Great Lakes to the Mississippi River. In Illinois, it ran 96 miles (154 km) from the Chicago River in Bridgeport, Chicago to the Illinois River at LaSalle-Peru. The canal crossed the Chicago Portage, and helped establish Chicago as the transportation hub of the United States, before the railroad era. It was opened in 1848. Its function was partially replaced by the wider and deeper Chicago Sanitary and Ship Canal in 1900, and it ceased transportation operations with the completion of the Illinois Waterway in 1933.

Illinois and Michigan Canal Locks and Towpath, a collection of eight engineering structures and segments of the canal between Lockport and LaSalle-Peru, was designated a National Historic Landmark in 1964.

The Chicago Area Waterway System (CAWS) is a complex of natural and artificial waterways extending through much of the Chicago metropolitan area, covering approximately 87 miles altogether. It straddles the Chicago Portage and is the sole navigable inland link between the Great Lakes and the Mississippi River and makes up the northern end of the Illinois Waterway.

The CAWS includes various branches of the Chicago and Calumet Rivers, as well as other channels such as the North Shore Channel, Cal-Sag Channel, and Chicago Sanitary & Ship Canal. The CAWS ends near the Lockport Navigational Pool, the highest elevated of the eight pools of the Illinois Waterway. There are three major locks within the CAWS, operated by the Army Corps of Engineers: the Chicago Harbor Lock, the Lockport Lock & Dam, and the T.J. O'Brien Lock and Dam.

The East North Central states is a region of the United States defined by the U.S. Census Bureau, containing five states: Illinois, Indiana, Michigan, Ohio and Wisconsin. These states border the Great Lakes, West North Central, the Southeastern, and Northeastern states; the Eastern North Central states also share a land border with Canada through Michigan's Upper Peninsula, southeastern, and mid-Michigan regions. As one of two subregional divisions used to categorize the Midwestern United States, East North Central closely matches the area of the Northwest Territory, excluding a portion of Minnesota.

The East North Central states also form a large part of the Great Lakes region, although the latter also includes Minnesota, New York, Pennsylvania and the Canadian province of Ontario. It has a low rate of population growth and the estimated population as of 2019 was 46,902,431, though the 2020 census numbered 47,368,533 residents. The Great Lakes bordering the area provide access to the Atlantic Ocean via the Great Lakes Waterway and St. Lawrence Seaway, or by the Erie Canal and the Hudson River, or via the Gulf of Mexico from the Mississippi River and the Illinois Waterway. Chicago and Detroit—two of East North Central's largest cities—are among the major ports of the United States.