what state is yellowstone park in?
For other uses, see Yellowstone (disambiguation). Yellowstone National Park is a national park located in the U.S. states of Wyoming, Montana and Idaho. It was established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872. Yellowstone was the first National Park in the U.S. and is also widely held to be the first national park in the world.