The Black Ridge Canyons Wilderness (BRCW) is located in western Colorado with a small portion extending into eastern Utah, USA, within the arid Colorado Plateau region approximately 15 miles (24 km) west of Grand Junction, Colorado. The wilderness lies on the northwest flank of the Uncompahgre Plateau. It is characterized by the high, east-west trending Black Ridge dissected by seven major canyon systems, draining into the Colorado River in Ruby Canyon. Elevations range from 4,700 feet (1,400 m) above sea level along the river to 6,800 feet (2,070 m). Canyons vary in length from several miles to twelve miles in length and may contain interesting side canyons. Geological features in these canyons include spires, windows, giant alcoves and desert varnish. Canyons may reach a depth of almost 1,000 feet (300 m), forming spectacular redrock cliffs. Spring runoff and summer thunderstorms create glistening waterfalls and plunge pools. Rattlesnake Canyon contains the second largest concentration of natural arches in the country.