The overall largest canyon in the world is the Grand Canyon in Arizona. It is 277 miles long, 18 miles wide at the widest points and averages a mile deep.
The Grand Canyon is contained within a 1,904-square-mile park divided into a North Rim and a South Rim section. Visitors looking down from the rim of the canyon can see several buttes, spires and mesas. These formations are actually mountains that are over 2,000 feet tall.
Though the Grand Canyon is very deep, the Cotahusi Canyon in Peru is the deepest in the world, boasting a depth of over 2 miles.