deep gorge of the Colorado River, in NW Ariz.: over 200 mi (322 km) long; 4-18 mi (6.4-29 km) wide; 1 mi (1.6 km) deep
See Grand Canyon in American Heritage Dictionary 4
A gorge of the Colorado River in northwest Arizona. It is up to 1.6 km (1 mi) deep, from 6.4 to 29 km (4 to 18 mi) wide, and more than 321.8 km (200 mi) long.