Willow River (Mississippi River)

The Willow River is a tributary of the Mississippi River, approximately 45 mi (72 km) long, in northern Minnesota in the United States.

It rises in Big Rice Lake, in the Chippewa National Forest in southeastern Cass County. It flows ESE to Haypoint, then ENE, then turns southwest, flowing around the eastern end of the Cuyuna Iron Range. It joins the Mississippi in Aitkin County, approximately 12 mi (19 km) northwest of Aitkin.

Willow River was so named from the growth of willows in what were swampy areas.