<Tr> <Th> Region </Th> <Td> The Americas </Td> </Tr> <Tr> <Th> Endangered </Th> <Td> 1995--2003 </Td> </Tr> <P> 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 . The park is known for its wildlife and its many geothermal features, especially Old Faithful geyser, one of its most popular features . It has many types of ecosystems, but the subalpine forest is the most abundant . It is part of the South Central Rockies forests ecoregion . </P> <P> Native Americans have lived in the Yellowstone region for at least 11,000 years . Aside from visits by mountain men during the early - to - mid-19th century, organized exploration did not begin until the late 1860s . Management and control of the park originally fell under the jurisdiction of the Secretary of the Interior, the first being Columbus Delano . However, the U.S. Army was subsequently commissioned to oversee management of Yellowstone for a 30 - year period between 1886 and 1916 . In 1917, administration of the park was transferred to the National Park Service, which had been created the previous year . Hundreds of structures have been built and are protected for their architectural and historical significance, and researchers have examined more than a thousand archaeological sites . </P>

When did yellowstone national park become a national park