Postcard of Old Faithful Geyser photographed by Asahel Curtis, 1928. Old Faithful is a cone geyser located in Wyoming, in Yellowstone NP. It was named in 1870 during the Washburn-Langford-Doane Expedition and was the first geyser in the park to receive a name. It is also known as one of the most predictable geographical features on Earth, erupting almost every 91 minutes. The geyser, as well as the nearby Old Faithful Inn, is part of the Old Faithful Historic District. Yellowstone National Park is a national park located primarily in the state of Wyoming, although it also extends into Montana and Idaho. It was established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872.