Grand Canyon National Park

Grand Canyon National Park, national park established in 1919, originally a forest reserve established in 1893. Located in northern Arizona, the park contains the world-famous Grand Canyon of the Colorado River and includes the river’s entire course from the southern end of Glen Canyon National Recreation Area to the eastern boundary of Lake Mead National Recreation Area. The great chasm has a maximum width of 29 km (18 mi) within the park, and it is about 1,500 m (5,000 ft) deep. The northern rim of the canyon is on the average 365 m (1,200 ft) higher than the southern rim and is closed to sightseers from October to May because of heavy winter snows. Paved roads wind around the rims of the Grand Canyon, and trails descend into the canyon, although only one of them, the Kaibab Trail, crosses the gorge from rim to rim.

The extreme variations in elevation from the depths of the canyon to the northern rim create four distinct zones of climate and plant life. Dense virgin forests of aspen, pine, fir, and spruce grow on the colder northern rim, and the southern rim is sparsely covered with piñon and juniper. Wildlife includes deer, pronghorn, puma, and bighorn sheep. Prehistoric Native Americans lived in the canyon and on its rims; ruins of pueblos and cliff dwellings remain. The park is bordered on the south by the reservation of the Havasupai people.

In 1975 the park was nearly doubled in size by the inclusion of Grand Canyon National Monument (proclaimed in 1932) and Marble Canyon National Monument (proclaimed in 1969) and portions of Glen Canyon and Lake Mead national recreation areas. The effects of tourism and federal water management policies have led the government to take steps to protect the canyon’s environment. The construction of Glen Canyon Dam in 1963 changed the ecology of the canyon by reducing the flow of the Colorado River and the sediment the river carried. Controlled floods through the Glen Canyon Dam are generated as a way to re-create natural spring flooding through the canyon and help restore the canyon’s natural ecosystems. In 1997 the government restricted small planes and helicopters from flying over the canyon and was considering other ways to limit the effects of tourism on the park. Administered by the National Park Service. Area, 492,666 hectares (1,217,403 acres).