Yellowstone National Park is a 2.2-million-acre landscape of high plateaus, forests, lakes, rivers and deep canyons in the northern Rocky Mountains. Most of it lies in Wyoming, with smaller portions extending into Montana and Idaho. The official road network forms a broad loop between entrances and visitor areas, but distances are deceptive: driving between famous stops can take much longer than a map suggests, and wildlife, construction or weather can slow traffic.
Congress established Yellowstone as a national park on March 1, 1872, creating a new form of federal landscape protection. The designation is why the park is often described as the world’s first national park, although the history of protected places is broader than a single American law. UNESCO added Yellowstone to the World Heritage List in 1978, recognizing its exceptional geothermal processes, ecosystems and scenery. Neither label means the land was empty before the park existed.