San Juan River (Colorado River) in the context of "Hovenweep National Monument"

The Colorado Plateau is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the Southwestern United States. This plateau covers an area of 336,700 km (130,000 mi) within western Colorado, northwestern New Mexico, southern and eastern Utah, northern Arizona, and a tiny fraction in the extreme southeast of Nevada. About 90% of the area is drained by the Colorado River and its main tributaries: the Green, San Juan, and Little Colorado. Most of the remainder of the plateau is drained by the Rio Grande and its tributaries.

The Colorado Plateau is largely made up of high desert, with scattered areas of forests. In the south-west corner of the Colorado Plateau, nicknamed High Country, lies the Grand Canyon of the Colorado River. Much of the Plateau's landscape is related to the Grand Canyon in both appearance and geologic history. The nickname "Red Rock Country" suggests the brightly colored rock left bare to the view by dryness and erosion. Domes, hoodoos, fins, reefs, river narrows, natural bridges, and slot canyons are only some of the additional features typical of the Plateau.

San Juan County (/sæn ˈwɑːn/ san-WAHN) is a county in the southeastern portion of the U.S. state of Utah. As of the 2020 United States census, the population was 14,518. Its county seat is Monticello, while its most populous city is Blanding. The Utah State Legislature named the county for the San Juan River, itself named by Spanish explorers (in honor of Saint John). San Juan County borders Arizona, Colorado, and New Mexico at the Four Corners.

Farmington is a city in the San Juan County, New Mexico, United States. As of the 2020 census, the city had a population of 46,624 people. Farmington (and surrounding San Juan County) makes up one of the four metropolitan statistical areas (MSAs) in New Mexico.

Farmington is located at the junction of the San Juan River, the Animas River, and the La Plata River, and is located on the Colorado Plateau. Farmington is the largest city of San Juan County, one of the geographically largest counties in the United States covering 5,538 square miles (14,340 km). Farmington serves as the commercial hub for most of northwestern New Mexico and the Four Corners region of four states. Farmington lies at or near the junction of several highways: U.S. Highway 64, New Mexico Highway 170, New Mexico Highway 371, and New Mexico Highway 516.

The Mancos River, formerly also El Rio de San Lazaro, is an 85.4-mile-long (137.4 km) northeast tributary of the San Juan River. It flows from the confluence of West Mancos River and East Mancos River near Mancos, Colorado, and joins the San Juan near Four Corners Monument in New Mexico.

The river was named after an incident during which a horse rider hurt his hand while crossing, the word Mancos being derived from Spanish meaning "one-armed".