Which U.S. national park was established first, when President Ulysses S. Grant signed its founding law in 1872?

Yellowstone National Park was established first, when President Ulysses S. Grant signed its founding law in 1872.

Grant signed the Yellowstone National Park Protection Act on March 1, 1872. The law set aside the Yellowstone region as a public park and prohibited private settlement, sale, or occupation of the land. Yellowstone is widely recognized as the first national park in the United States and is commonly described as the world’s first national park.

The park’s creation followed scientific and artistic expeditions that documented its geysers, hot springs, canyons, and wildlife. The 1871 Hayden Geological Survey produced influential reports, photographs, and paintings that helped persuade Congress to protect the area. Indigenous peoples had lived in and used the region for thousands of years before the park was created.

Yellowstone is primarily in Wyoming, with smaller sections in Montana and Idaho. The National Park Service did not yet exist in 1872; it was created in 1916, and Yellowstone’s administration was later transferred to it.