President Ulysses S. Grant signed the law creating Yellowstone National Park on March 1, 1872.
The Yellowstone National Park Protection Act set aside a large area around the Yellowstone River and its geothermal features as a public park. It made Yellowstone the first national park in the United States and is widely regarded as the first national park in the world.
The legislation followed government-sponsored exploration, especially the Hayden Geological Survey of 1871. Photographs by William Henry Jackson and paintings by Thomas Moran helped Americans understand the region’s dramatic landscapes, geysers, and waterfalls. Reports from the expedition persuaded Congress that the area should be protected rather than opened to private development.
Yellowstone is located mainly in Wyoming, with smaller portions in Montana and Idaho. The U.S. Army managed the park from 1886 until the National Park Service assumed responsibility in 1917. Native peoples had used the region for thousands of years before its designation as a national park.