Old Faithful is one of the most well-known geysers in the world. This incredible natural feature has been drawing visitors for more than a century. However, despite its celebrity, there is still plenty most people don’t know about Yellowstone’s most popular geyser.
So here is a brief history of Old Faithful, along with a few little-known facts about this famous landmark for a better understanding the next time you tour Yellowstone.
Old Faithful was named by the Washburn Expedition of 1870, who explored the area that would later be called Yellowstone. Members of the expedition entered the Upper Geyser Basin after traveling down the Firehole River and saw the geyser, which they called Old Faithful because of the regularity with which it erupted.
Geysers like Old Faithful are only formed under specific conditions, making them relatively rare. Magma under the Earth’s surface superheats pockets of underground water, building pressure that eventually pushes the water upwards. Rhyolite, a volcanic rock high in silica content, lines the tunnel through which the water escapes its underground pocket, creating a pipe that can withstand the incredible heat and pressure as the water erupts above ground.