McDermitt Caldera is possibly the oldest caldera in a sequence of calderas formed by the Yellowstone Hotspot. The caldera was formed when a lava dome made of rhyolite collapsed in an eruption between 16.37 and 16.41 million years ago. The lava dome had been built by volcanic eruptions starting about 19 million years ago. The highest point in the McDermitt Caldera is Jordan Meadow Mountain, part of the Montana Mountains, which is at its peak elevation.