Mesa Falls Tuff is a volcanic tuff formation in Idaho west of Yellowstone National Park, created about 1.3 million years ago by the Mesa Falls eruption. That eruption formed the Henry's Fork Caldera and was the second most recent caldera-forming event linked to the Yellowstone hotspot, ejecting about 280 cubic kilometers of material. It came after the Huckleberry Ridge Tuff and before the Lava Creek Tuff in the sequence of major Yellowstone hotspot eruptions, making it an important part of the volcanic history that shaped the Snake River Plain and the greater Yellowstone region.