The Grand Canyon is a steep-sided canyon carved by the Colorado River in the United States in the state of Arizona. A powerful and inspiring landscape, the Grand Canyon overwhelms our senses through its immense size; 277 river miles (446km) long, up to 18 miles (29km) wide, and a mile (1.6km) deep. [16] Nearly two billion years of the Earth’s geological history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted.