Ulysses S. Grant signed the act that established Yellowstone National Park in 1872.

In 1872, President Ulysses S. Grant signed the act that officially established Yellowstone National Park. This landmark legislation created the first national park in the United States, and arguably the world, setting aside a vast area of natural beauty and geothermal wonders for preservation and public enjoyment. Yellowstone's establishment marked a significant milestone in conservation history.