Yellowstone National Park
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho.
Sources
http://www.yellowstone.co/
http://www.nps.gov/yell/index.htm
http://en.wikipedia.org/wiki/Yellowstone_National_Park