The United States established Yellowstone as the world’s first national park in 1872.
President Ulysses S. Grant signed the Yellowstone National Park Protection Act on March 1, 1872. The law reserved a large area in the territories of Montana and Wyoming as a public park for the benefit and enjoyment of the people.
Yellowstone’s geothermal features, including geysers, hot springs, mud pots, and fumaroles, helped persuade lawmakers that the landscape should be protected rather than privately exploited. The park also contains the Yellowstone Caldera, a volcanic system responsible for much of its geothermal activity.
The national-park idea later spread across the United States and the world. Yellowstone is famous for Old Faithful, but the geyser is not the park’s largest or most powerful geothermal feature. The park’s history also includes the displacement of Indigenous peoples and long-standing Indigenous relationships with the region.