Old Faithful in Yellowstone National Park.
Old Faithful is a geyser located Yellowstone National Park, in the American state of Wyoming.
In 1850, as Daniel Clayton and Martha O'Brien crossed the Oregon Trail, they converged in northern Wyoming in what would later be Yellowstone National Park. When Doc, Jules, Verne, and Marty McFly visited, they recognized Old Faithful.
Martha and Verne sat on a buffalo hide, and were lifted up by the Old Faithful geyser. They were then saved by a glider flown by Doc and Daniel Clayton.