Ontonagon is a village in the U.S. state of Michigan. As of the 2000 census, the village had a total population of 1,769. 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. The main industry centers on the Smurfit-Stone Container production facility at the river mouth. According to the United States Census Bureau, the village has a total area of 10.0 square kilometers (3.9 square miles). 9.7 square kilometres (3.8 square miles) of it is land and 0.3 square kilometres (0.1 square miles) of it is water. The total area is 3.35% water.

The Porcupine Mountains, also called the Porkies, are a group of small mountains that spans across the northwestern Upper Peninsula of Michigan in Ontonagon and Gogebic counties, near the shore of Lake Superior. The area is part of the Porcupine Mountains Wilderness State Park. The Porcupine Mountains were named by the native Ojibwa people, apparently because their silhouette had the shape of a porcupine. The popular Lake of the Clouds is in the heart of the mountains.