La Plata Mountains in the context of "Montezuma County, Colorado"

La Plata County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 55,638. The county seat is Durango. The county was named for the La Plata River and the La Plata Mountains. "La plata" means "the silver" in Spanish. La Plata County comprises the Durango, CO Micropolitan Statistical Area. The county is home to Durango Rock Shelters Archeology Site, the type site for the Basketmaker II period of Anasazi culture.

La Plata River (Navajo: Tsé Dogoi Ńlíní) is a 70-mile-long (110 km) tributary to the San Juan River in La Plata County, Colorado, and San Juan County, New Mexico, in the United States. This small river heads at the western foot of Snow Storm Peak in the La Plata Mountains of southwestern Colorado, approximately 35 miles (56 km) north of the New Mexico state line. It flows in a southerly direction until it joins the San Juan at the western edge of the city of Farmington, New Mexico, about 19 miles (31 km) south of the Colorado state line.

The Navajo name for the river, Tsé Dogoi Nlini translates as "flowing over projecting rock".

The Colorado Mineral Belt (CMB) is an area of ore deposits from the La Plata Mountains in Southwestern Colorado to near the middle of the state at Boulder, Colorado, and from which over 25 million troy ounces (778 t) of gold were extracted beginning in 1858. The belt is a "northeast-striking zone defined by: a Proterozoic shear zone system (McCoy, 2001); a suite of Laramide-aged plutons and related ore deposits (Tweto and Sims, 1963); a major gravity low (Isaacson and Smithson, 1976); low-crustal velocities; and high heat flow (Decker et al., 1988)." Mining districts include:[1]

• Central City-Idaho Springs district
• Leadville mining district, named for Leadville, Colorado
• Sneffels-Red Mountain-Telluride district

The belt lies within a zone that has been geologically active at intervals beginning from near the time of crustal accretion in central Colorado at least 1.6 billion years ago until the present. Parts of the CMB follow shear zones of Precambrian age and the Paleozoic and Mesozoic. Igneous rocks intruded about 60 to 70 million years ago during the Laramide orogeny are associated with the belt and once were thought to be responsible for most of the ore deposits. Now many of the important ore deposits are thought to be genetically related to younger magmatism, some at least as young as about 25 million years.