Postcard of the Lower Falls photographed by Asahel Curtis, 1928. Yellowstone Falls consist of two major waterfalls on the Yellowstone River, within Yellowstone National Park. As the Yellowstone river flows north from Yellowstone Lake, it leaves the Hayden Valley and plunges first over Upper Yellowstone Falls and then a quarter mile downstream over Lower Yellowstone Falls, at which point it then enters the Grand Canyon of the Yellowstone, which is up to 1,000 feet deep. The lower falls are 308 feet high, or almost twice as high as Niagara. The lower falls descend from the 590,000 year old Canyon Rhyolite lava flow. The lower falls of the Yellowstone is still the largest volume major waterfall in the Rocky Mountains of the United States. Yellowstone National Park is a national park located primarily in the state of Wyoming, although it also extends into Montana and Idaho.