The Yellowstone Caldera, sometimes referred to as the Yellowstone Supervolcano, is a volcanic caldera and supervolcano in Yellowstone National Park in the Western United States. The caldera and most of the park are located in the northwest corner of Wyoming. The caldera measures 43 by 28 miles (70 by 45 kilometers), and postcaldera lavas spill out a significant distance beyond the caldera proper.