Lower Yellowstone Falls is the tallest waterfall in Yellowstone at 308 feet (94 meters) - twice the height of Niagara Falls. Located in the Grand Canyon of the Yellowstone with its distinctive yellow walls that gave the park its name. Upper Yellowstone Falls nearby is 109 feet tall. Popular viewing spots include Artist Point and Lookout Point. The canyon stretches 20 miles with walls reaching 1,200 feet deep.