The Grand Canyon of the Yellowstone is the first large canyon on the Yellowstone River downstream from Yellowstone Falls in Yellowstone National Park in Wyoming. The canyon is approximately 24 miles (39 km) long, between 800 and 1,200 ft (240 and 370 m) deep and from .25 to .75 mi (0.40 to 1.21 km) wide.The present canyon is no more than 10,000 to 14,000 years old, although there has probably been a canyon in this location for a much longer period.The specifics of the geology of the canyon are not well understood, except that it is an erosional feature rather than the result of glaciation. After the caldera eruption of about 600,000 years ago, the area was covered by a series of lava flows.
