Mount Adams is a potentially active stratovolcano in the Cascade Range and the second-highest mountain in the U.S. state of Washington.[7] Adams is a member of the Cascade Volcanic Arc, and is one of the arc's largest volcanoes,[8] located in a remote wilderness approximately 31 miles (50 km) east of Mount St. Helens.[9] The Mount Adams Wilderness comprises the upper and western part of the volcano's cone. The eastern side of the mountain is part of the Yakama Nation.[10][11]