The Oneonta Gorge is in the Columbia River Gorge in the American state of Oregon. The U.S. Forest Service has designated it as a botanical area because of the unique aquatic and woodland plants that grow there. Exposed walls of 25 million year old (Miocene epoch) basalt are home to a wide variety of ferns, mosses, hepatics and lichens, many of which grow only in the Columbia River Gorge.