San Juan River

The San Juan River is a major tributary of the Colorado River in the Southwestern United States, providing the chief drainage for the Four Corners region of Colorado, New Mexico, Utah, and Arizona. Originating as snowmelt in the San Juan Mountains (part of the Rocky Mountains) of Colorado, it flows 383 miles (616 km) through the deserts of northern New Mexico and southeastern Utah to join the Colorado River at Glen Canyon. The river drains a high, arid region of the Colorado Plateau. Along its length, it is often the only significant source of fresh water for many miles. The San Juan is also one of the muddiest rivers in North America, carrying an average of 25 million US tons (22.6 million t) of silt and sediment each year. Historically, the San Juan formed the border between the territory of the Navajo in the south and the Ute in the north. Although Europeans explored the Four Corners region as early as the 1700s, it was not settled until the gold and silver booms of the 1860s, when settlers arrived in large numbers from the eastern United States. After heated conflicts over land, the Native Americans were forced into reservations, where their descendants live today. During the 20th century, intensive drilling in the fossil-fuel rich San Juan Basin and uranium mining along the lower river in Utah generated serious concerns about water quality, particularly in the Navajo Nation where the river is a crucial source of water for irrigation. Runoff from abandoned gold and silver

Flows through: United States.

River data from Wikidata (CC0); lengths normalised to a common unit.