Yellowstone Falls consists of two major waterfalls on the Yellowstone River, within Yellowstone National Park, Wyoming, United States. As the Yellowstone River flows north from Yellowstone Lake, it leaves the Hayden Valley and plunges first over Upper Falls of the Yellowstone River and then a quarter mile (400 m) downstream over Lower Falls of the Yellowstone River, at which point it then enters the Grand Canyon of the Yellowstone, which is up to 1,000 feet (304 m) deep.

Source: Wikipedia