Ontonagon River
General data
- Name: Ontonagon River
- Water system: St. Lawrence River
- Water type: River
- Source: Middle Branch Ontonagon River, West Branch Ontonagon River
- Progression: Lake Superior -> St. Marys River (Michigan–Ontario) -> Lake Huron -> St. Clair River -> Lake St. Clair (North America) -> Detroit River -> Lake Erie -> Niagara River -> Lake Ontario -> St. Lawrence River -> Gulf of St. Lawrence -> Atlantic Ocean -> Planet Earth
- Climates: Continental
- Continents: North America
- Countries: United States of America
The Ontonagon River is a river flowing into Lake Superior at the village of Ontonagon, on the western Upper Peninsula of Michigan in the United States. The main stem of the river is 25 miles (40 km) long and is formed by a confluence of several longer branches, portions of which have been collectively designated as a National Wild and Scenic River. Several waterfalls occur on the river including Agate Falls and Bond Falls.