The Montreal River is a river flowing to Lake Superior in northern Wisconsin and the Upper Peninsula of Michigan in the United States. It is 47.8 miles (76.9 km) long and drains approximately 270 square miles (700 km2) in a forested region. For most of its length, the river's course defines a portion of the Wisconsin–Michigan border. The Ojibwe name for the river is Gaa-waasijiwaang, meaning "where there is whitewater".