Because there is no well-defined minimum size for a "supervolcano," there is no exact number of such volcanoes. Examples of volcanoes that produced exceedingly voluminous pyroclastic? eruptions and formed large calderas in the past 2 million years would include Yellowstone, [Long Valley]? in eastern California, Lake Toba in Indonesia, and Taupo? in New Zealand. Other "supervolcanoes" would likely include the large caldera volcanoes of Japan, Indonesia, Alaska (e.g. Aniakchak?, Emmons?, Fisher?), and other areas.
Another type of eruption that can be classified as a "supervolcano" is the basaltic flood variety that formed the Deccan Traps in India and the Columbia River basalts of the northwestern United States. These volcanoes probably didn't erupt as explosively as the caldera-forming ones, but instead flooded vast regions with thick layers of lava in a short period of time.