Old Faithful Geyser erupting with other smaller geysers in spring in the Upper Geyser Basin area, Yellowstone National Park. This location contains the largest concentration and nearly one-quarter of all the geysers in the world. A variety of thermal features exist here: spouting geysers, colorful hot springs, and steaming fumaroles. Old Faithful was named by the Washburn expedition of 1870. They were impressed by its size and frequency. It is not the biggest or most regular geyser in Yellowstone, but it is the biggest regular geyser. It has been erupting in nearly the same fashion throughout the recorded history of Yellowstone.