The San Juan River, named by the Spanish San Juan Bautista (Saint John the Baptist), threads its way through Colorado, New Mexico, and Utah to the border of northern Arizona. With its headwaters in the San Juan Mountains of southwestern Colorado from which comes ninety percent of its flow, the river still drains nearly sixteen million acres of the Four Corners region as it drops from an altitude of 14,000 feet to approximately 3,600 feet above sea level. The flow of the river today is largely controlled by the waters released from Navajo Dam in New Mexico into the San Juan. The river's Utah portion is approximately 125 miles long; it then terminates as it flows into Lake Powell.

The river historically has played an important part as a continuous source of water in an arid climate. Anasazi ruins and rock-art panels dot its sandstone cliffs and floodplains. The San Juan also plays a significant role in Navajo mythology, where it is known as Old Age River, One-With-a-Long-Body, or One-With-a-Wide-Body, and is characterized variously as an old man with hair of white foam, a snake coiled at the Goosenecks, a flash of lightning, and a black club of protection. This latter theme is important to the Navajos, who, even before the river became an official reservation boundary in 1884, viewed it as a line of separation between their safe confines and the land of the Utes and white men.

The first substantial Anglo settlement on the Utah portion of the San Juan occurred at Riverside (Aneth) in 1878-79 when eighteen families from Colorado established a small community more than a year before the Mormons made their trek through the Hole-in-the-Rock and settled Bluff. Through the 1880s and early 1890s, trading posts flourished as Navajos herded sheep and planted small horticultural plots while the settlers struggled to prevent destructive flooding.

In addition to agriculture, the San Juan has been the focus of a variety of economic endeavors. During the 1890s and early 1900s, there were futile attempts to find gold and the beginning of an interest in oil. Oil companies in the 1920s started drilling in earnest, giving rise to a petroleum industry that is still in operation today near the river towns of Aneth, Montezuma Creek, Bluff, and Mexican Hat. By the 1940s Norman Nevills and Jack Frost dominated the river-running business and took hundreds of tourists down the San Juan. This industry continues to grow, and the Bureau of Land Management has had to restrict in an attempt to keep the river experience safe and enjoyable for all.