The Wisconsin River is a tributary of the Mississippi River in the U.S. state of Wisconsin. At approximately 430 miles long, it is the state's longest river. The river's name was first recorded in 1673 by Jacques Marquette as "Meskousing", which is rooted in the Algonquian languages used by the area's Native American tribes. The river's original meaning is obscure, but French explorers who followed in the wake of Marquette later modified the name to "Ouisconsin", and so it appears on Guillaume de L'Isle's map. This was simplified to "Wisconsin" in the early 19th century, before being applied to Wisconsin Territory and finally the state of Wisconsin.

Wisconsin is a state in the Upper Midwestern region of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin is the 25th-largest state by land area and the 20th-most populous.