The Huckleberry Ridge Tuff is a tuff formation created by the Huckleberry Ridge eruption that formed the Island Park Caldera that lies partially in Yellowstone National Park, Wyoming and stretches westward into Idaho into a region known as Island Park. This eruption of 2,450 km3 of material is thought to be one of the largest known eruptions in the Yellowstone hotspot's history. This eruption, 2.1 million years ago, is the third most recent large caldera-forming eruption from the Yellowstone hotspot. It was followed by the Mesa Falls Tuff and the Lava Creek Tuff eruptions. The eruption likely occurred in 3 phases, separated by decades.