Yellowstone takes its name from the yellow volcanic rocks and soil found throughout the area.
John Colter visited Yellowstone in 1807. It wasn't until the Hayden expedition of 1870 brought back paintings by Thomas Moran that early stories of the mountain men began to be accepted.
Yellowstone became the first national park in 1872.
At 3,742 square miles, Yellowstone is roughly the size of Connecticut.
Yellowstone is actually the caldera of a massive volcano. 600,000 years ago a massive eruption blew 600 cubic miles of debris into the atmosphere. Ash eventually covered much of the eastern half of the United States.
