The Wolf River is a 225 mi (362 km) long tributary of the Fox River in northeastern Wisconsin in the Great Lakes region of the United States. The river is one of the two National Scenic Rivers in Wisconsin, along with the St. Croix River. The scenic portion is 24 miles (39 km) long. The river and its parent the Fox River and associated lakes are known for their sturgeon which spawn every spring upstream on the lower river until blocked by the Shawano Dam. The river flows through mostly undeveloped forestland southerly from central Forest County in the north to Lake Poygan in the south. The lake is part of the Winnebago Pool of lakes fed by both the Fox and Wolf Rivers. The Fox-Wolf basin is usually considered to be a single unified basin and the rivers themselves may be referred to as the Fox-Wolf River system.

The Fox River is a river in eastern Wisconsin in the Great Lakes region of the United States. It is the principal tributary of Green Bay, and via the Bay, the largest tributary of Lake Michigan. The city of Green Bay, one of the first European settlements in the interior of North America, is on the river at its mouth on lower Green Bay.