is an immense gorge cut by the Colorado River into the high plateau in the northwestern corner of Arizona. It ranges in width from 4 to 18 miles. The Colorado River, which is more than a mile below the rim in some areas of the canyon, extends in a winding course from the head of Marble Gorge to Grand Wash Cliffs, a distance of about 280 miles

The Canyon was formed by the ceaseless cutting of the silt-laden Colorado River, accelerated by storm waters that occasionally fall into the Canyon, and by weathering processes. While the river has been cutting its way downward, the land in the plateau region that surrounds it has been gradually rising. The Grand Canyon is a relatively new geologic feature, even though the work of "making" it has been going on for more than a million years.

Although the canyon is "new," the beds of rock exposed in it are old; they tell a story that began many millions of years ago. Most of the layers of rock in the walls of the canyon are sandstone and limestone and shale. These rocks are water-made, meaning that for millions of years this region was actually under the sea. At the very bottom of the canyon the rock is granite, which was formed from hot liquid rock like the lava that pours out of volcanoes. This layer was formed long before there were any people on earth, long before the days of the dinosaurs, even before the time when trilobites were the earth's leading animals.

The first white man to see the Grand Canyon was Garcia López de Cárdenas, who had been sent from Zuñi, New Mexico, to find a river far to the west, the existence of which had been learned from the natives. In 1854 Lieutenant A.W. Whipple followed the lower course of the Colorado River as far up as the mouth of Diamond creek. In 1857 Lieutenant J.C. Ives travelled through the gorge of Diamond Creek and eastward to Havasu Canyon, the San Francisco Mountains, the Little Colorado and the country of the Hopi Indians.

Grand Canyon National Park, which includes 250 miles of the most magnificent and deepest part of the Grand Canyon of the Colorado, was created by the United States Congress in 1919. Numerous observation platforms provide wonderful panoramic views of the canyon, and there are dozens of trails that take visitors from the rim to the river.

Questions or comments about this page?