The Copper Canyon is a group of canyons consisting of 6 distinct canyons in the Sierra Tarahumara in the southwestern part of the state of Chihuahua in Mexico. The overall canyon system is larger and portions are deeper than the Grand Canyon in the neighboring United States. The canyons were formed by six rivers which drain the western side of the Sierra Tarahumara (a part of the Sierra Madre Occidental). All six rivers merge into the Rio Fuerte and empty into the Sea of Cortez. The walls of the canyon are a copper/green color which is where the name originates.