Grand Canyon great gorge of the Colorado River, one of the natural wonders of the world; c.1 mi (1.6 km) deep, from 4 to 18 mi (6.4–29 km) wide, and 217 mi (349 km) long, NW Ariz. The canyon shows in its rocks the repeated geological sequence of uplift, erosion (due to the river's constant wearing force), submergence, and deposition of materials. The multicolored rocks, the steep and embayed rims, and the isolated towers, mesas, "temples," and other eroded rock forms catch the contrast of sun and shadow and glow with changing hues of great beauty. Plant life on the canyon walls varies from subtropical at the base to subarctic near the rims. Hundreds of ancient pueblos dot the lower canyon walls and the rim. The Havasupai people still occupy a part of the canyon, and the Hualapai reservation encompasses much of the south rim. (The Hualapai now operate a visitors center, including a skywalk projecting over the canyon rim.) The first European to see the canyon was the Spanish explorer García López de Cárdenas in 1540. In 1869 the U.S. explorer John Wesley Powell became the first person to lead a party through the canyon bottom in a boat.

The Grand Canyon was set aside by the U.S. government in 1908 as a national monument. In 1919 an expanded area was designated Grand Canyon National Park (1,217,403 acres/492,876 hectares). The park was enlarged in 1975 to include other areas, such as Marble Canyon and parts of Glen Canyon and Lake Mead. Along the forested northern rim and the more accessible southern rim are numerous lookouts, and trails wind to the canyon floor. Raft and boat excursions along the canyon's river bottom are popular. In 2000 the lands north of the western portion of the canyon, an area almost the size of the park, were designated Grand Canyon–Parashant National Monument (1,014,000 acres/410,670 hectares). See National Parks and Monuments (table).

Bibliography: See S. Whitney, A Field Guide to the Grand Canyon (1987); J. W. Krutch, Grand Canyon (1989); S. J. Pyne, How the Canyon Became Grand (1998).

Grand Canyon. Arguably the single best‐known American place, the Grand Canyon of the Colorado River is about a mile deep, twelve miles wide on average, and winds for 279 miles across the desert plateaus of northern Arizona. The chasm begins fourteen miles downstream from Glen Canyon Dam (1966), which forms Lake Powell. The lower forty miles of the Grand Canyon contains the headwaters of Lake Mead, which results from Hoover Dam (1936).

Although long known to and used by American Indians, the Grand Canyon was first viewed by Europeans in 1540, when Francisco Vásquez de Coronado sent a small detachment of explorers to the South Rim. But the complex region below the rim was still unknown wilderness in 1869 when the one‐armed Civil War veteran, John Wesley Powell, led a small group down the Colorado River and through the canyon. Powell's three‐month journey made him a legend of the American imagination. Thomas Moran's paintings of the 1870s and Ferde Grofé’s Grand Canyon Suite (1931) confirmed the Grand Canyon's status as an icon of sublime, romantic scenery.

A spur line from the Santa Fe Railroad to the South Rim, completed in 1901, opened the era of modern tourism. Parts of the canyon were designated a national park in 1919, but the act left a loophole for hydropower dams. In 1968, after a bitter political struggle, Congress prohibited the damming of the Grand Canyon. By the 1990s, the Canyon was most threatened by the five million people who visited its rims and the 25,000 who traveled the river every year.
See also Environmentalism; National Park System.

Bibliography

Robert Wallace , The Grand Canyon, 1972.
J. Donald Hughes , In the House of Stone and Light: A Human History of the Grand Canyon, 1978.

Roderick Frazier Nash

GRAND CANYON

GRAND CANYON, a gorge of the Colorado River, from four to eighteen miles wide and in places more than

a mile deep, winding some 280 miles from Marble Canyon, near the Arizona-Utah line, to Grand Wash Cliffs in northern Mohave County of Arizona.

The first written description of the canyon is Pedro de Castañeda's account of a small group of Spanish explorers who found it after hearing stories of a large canyon during a visit to the Hopis in 1540. The canyon was little known until Lt. Joseph C. Ives and Dr. J. S. Newberry visited its lower end in April 1858 and brought back the first geological description of the region. Maj. John Wesley Powell made the first journey down the Colorado River through the canyon with nine men, 24 May–30 August 1869. Congress created Grand Canyon National Park, 673,575 acres, on 26 February 1919, and two years later the completion of a railroad from Williams, Arizona, facilitated tourist travel to the canyon. In 1932, an additional 198,280 acres encompassing Toroweap Point of the canyon was set aside as the Grand Canyon National Monument. In 1966, the Sierra Club successfully spearheaded a drive to prevent the erection of a dam at the lower end of the canyon.

BIBLIOGRAPHY

Morehouse, Barbara J. A Place Called Grand Canyon: Contested Geographies. Tucson: University of Arizona Press, 1996.

Pyne, Stephen J. How the Canyon Became Grand: A Short History. New York: Viking, 1998.

Rufus Kay Wyllys / c. w.

See also Colorado River Explorations ; Explorations and Expeditions: Spanish ; National Park System ; Tourism .

Grand Canyon Deep gorge in nw Arizona, USA, carved by the Colorado River. It is 450km (280mi) long, and varies from 6km (4mi) to 18km (11mi) in width. With its magnificent multicoloured rock formations revealing hundreds of millions of years of geological history, the Grand Canyon is one of the great wonders of the natural world.

http://www.nps.gov/grca