Encyclopædia Britannica, Ninth Edition/Colorado River

COLORADO RIVER, or Rio Colorado, a large river of North America, which rises in the Rocky Mountains and falls into the Gulf of California. The main stream, known as the Green River, has its source in Fremont's Peak on the western borders of Wyoming, so that the whole extent of its course must be upwards of 2000 miles. After receiving the waters of the Yampuh and the White River, it flows south for about 150 miles without any important augmentation till it meets with the great rival stream of the Grand River, which by means of its numerous confluents drains so large a portion of the western versant in the State of Colorado. The united stream continues to force its way south, till at its junction with the Colorado Chiquito, or Little Colorado, which takes its rise in the Sierra Madre of New Mexico, it turns almost due west, and cuts right athwart the line of the mountain ranges. Its southern direction is resumed after the confluence of the Virgen from the Wahsatch Mountains, and it only receives one other tributary of real magnitude, the River Gila, before it reaches the sea. The enormous cañons or ravines through which the Colorado and several of its confluents force their way, render this one of the most remarkable river systems of the world. The Grand Cañon alone extends for a distance of about 200 miles westward from the junction of the Colorado Chiquito, and its walls rise almost sheer from the water's edge to a height of from 4000 to as much as 7000 feet. Further down is Black Cañon which, with a length of 25 miles and a height of 1000 or 1500 feet, would be considered a magnificent phenomenon, were it not so completely thrown into insignificance by its more stupendous neighbour. These very features which give the river its uniqueness prevent it from being of much use as a means of navigation; but steamers can proceed upwards as far as Callville, about 612 miles from the mouth.

The discovery of the Colorado is due to Fernando Alascon in 1540; but it was not till Lieutenant Ives's expedition in 1857 that even the lower part of its course was properly explored. The mysteries of the Great Cañon were first invaded by an unlucky “prospector,” James White, who along with a companion thought it safer to trust himself to the river than to the Indians. In 1869 the whole course from the head-waters in Wyoming to the town of Callville was traversed by a party of explorers, commissioned by the United States Government and commanded by Professor J. W. Powell. Since that date the river and its basin have been the object of systematic survey under the same auspices, and the results of the gigantic undertaking have been published by Professor Powell in his Exploration of the Colorado River of the West and its Tributaries, explored in 1869, 1870, 1871, and 1872 (Washington, 1875).