Which national park is home to the geyser Old Faithful?

Old Faithful is located in Yellowstone National Park, in Wyoming, United States. The famous cone geyser stands in the park’s Upper Geyser Basin.

Yellowstone contains one of the world’s greatest concentrations of geothermal features, including geysers, hot springs, mudpots, and fumaroles. Old Faithful became famous because its eruptions are unusually predictable, although it is not the tallest or largest geyser in the park. Its eruption interval varies, and the timing depends partly on the duration of the previous eruption.

Members of the Washburn–Langford–Doane Expedition named Old Faithful in 1870. Early visitors even used its hot water to wash clothes, but modern visitors must stay on designated boardwalks because the thermal ground can be dangerously thin and the water can be near boiling. Yellowstone’s Steamboat Geyser is taller, while Old Faithful remains the park’s best-known geyser because of its regularity and long history of public observation.