Ontonagon (/ˌɒntəˈnɑːɡən/ ON-tə-NAH-gən) is a village in the U.S. state of Michigan. The population was 1,494 at the 2010 census. It is the county seat of Ontonagon County.
The village is located within Ontonagon Township, at the mouth of the Ontonagon River on Lake Superior. Industry was centered on the Smurfit-Stone Container production facility at the river mouth until the plant closed in 2010.