[5][6] The Montreal River issues from Pine Lake in the town of Oma in eastern Iron County in northern Wisconsin.

It flows initially northwardly to the boundary between Iron County and Gogebic County, Michigan, then northwestwardly along the state line, past the 'twin cities' of Hurley, Wisconsin and Ironwood, Michigan.

Downstream of Ironwood and Hurley the Montreal River passes over four named waterfalls.

The river enters Oronto Bay on the southwestern shore of Lake Superior approximately 15 miles (24 km) northwest of Ironwood, at Michigan's westernmost point.

The rivers are located in the Laurentian Mixed Forest Province (north woods) region of the upper midwest.