The Great Lakes region of North America includes the eight U.S. states of Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania and Wisconsin as well as the Canadian province of Ontario. The region borders the Great Lakes and forms a distinctive historical, economic, and cultural region. The Great Lakes Commission, authorized by the eight American states and Ontario, confirmed by the Canadian and American federal governments recognizes a formal U.S. - Canadian International Great Lakes Region, with the additional inclusion of the Canadian Province of Quebec.

The Great Lakes Region takes its name from the corresponding geological formation of the Great Lakes Basin, a narrow watershed encompassing The Great Lakes, among watersheds to the region's north (Hudson Bay), west (Mississippi), east and south (Ohio). To the east, the rivers of St. Lawrence, Richelieu, Hudson, Mohawk and Susquehanna form an arc of watersheds east to The Atlantic.

The Great Lakes region, as distinct from The Great Lakes Basin, defines a unit of political entities defined by the U.S. states and the Canadian Province of Ontario encompassing the Great Lakes watershed, and bordering one or more lakes.

The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada–United States border which connect to the Atlantic Ocean through the Saint Lawrence Seaway and the Great Lakes Waterway. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth comprising 21% of the world's surface fresh water. The total surface is 94,250 square miles (244,106 km²), and the total volume (measured at the low water datum) is 5,439 cubic miles (22,671 km³). The lakes are sometimes referred to as the North Coast or "Third Coast" by some citizens of the United States.

The lakes have been a major source of trade through this area, and they are home to a large number of aquatic species. Many invasive species have been introduced due to trade in the area, and some threaten the biodiversity of the area.

Though the five lakes reside in separate basins, they form a single, naturally interconnected body of fresh water. The lakes form a chain connecting the east-central interior of North America to the Atlantic Ocean. From the interior to the outlet at the St. Lawrence River, water flows from Superior to Michigan-Huron (in the hydrological sense, a single body of water), southward to Erie, and finally northward to Lake Ontario. The lakes drain a large watershed via many rivers, and are studded with approximately 35,000 islands. The Great Lakes region contains not only the five themselves but also many thousands of smaller lakes, often called inland lakes. Of the five lakes, Lake Michigan is the only one that is located entirely within the United States; the others form a water border between the United States and Canada.