The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that includes Arizona and New Mexico, along with adjacent portions of California, Colorado, Nevada, Oklahoma, Texas, and Utah. The largest cities by metropolitan area are Phoenix, Las Vegas, El Paso, Albuquerque, and Tucson. Before 1848, in the historical region of Santa Fe de Nuevo México as well as parts of Alta California and Coahuila y Tejas, settlement was almost non-existent outside of Nuevo México's Pueblos and Spanish or Mexican municipalities. Much of the area had been a part of New Spain and Mexico until the United States acquired the area through the Treaty of Guadalupe Hidalgo in 1848 and the smaller Gadsden Purchase in 1854.
The Four Corners is a region of the Southwestern United States consisting of the southwestern corner of Colorado, southeastern corner of Utah, northeastern corner of Arizona, and northwestern corner of New Mexico. Most of the Four Corners region belongs to semi-autonomous Native American nations, the largest of which is the Navajo Nation, followed by Hopi, Ute, and Zuni tribal reserves and nations. The Four Corners region is part of a larger region known as the Colorado Plateau and is mostly rural, rugged, and arid.
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 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.
Southwestern Colorado is a region in the southwest portion of Colorado, which in turn is part of the larger Four Corners region. It is bordered by Western Colorado, Southern Colorado, the south portion of Central Colorado, Utah, and New Mexico.
The Colorado River cutthroat trout is a subspecies of cutthroat trout native only to the Green and Colorado River basins, which are west of the Continental Divide. Cutthroat trout found in other river basins belong to other subspecies.
Heterotheca is a genus of North American plants in the family Asteraceae.
Muhlenbergia is a genus of plants in the grass family.
Berlandiera is a genus of flowering plants in the family Asteraceae.
Chaetopappa ericoides is a species of flowering plant in the family Asteraceae known by the common names rose heath and heath-leaved chaetopappa. It is native to the southwestern and western Great Plains regions of the United States, plus northern Mexico. It is found in California, Nevada, Arizona, Utah, New Mexico, Colorado, Wyoming, Texas, Oklahoma, Kansas, Nebraska, Chihuahua, Coahuila, Sonora, Durango, Zacatecas, San Luis Potosí, and Nuevo León.
Artemisia nova is a North American species of sagebrush, known by the common name black sagebrush. It is "one of the most common shrubs in the western United States".
Frangula betulifolia, the birchleaf buckthorn, is a shrub or small tree in the buckthorn family, Rhamnaceae. It is native in northern Mexico in the Sierra Madre Occidental cordillera, and mountainous, desert regions of the Southwestern United States of Arizona, Utah, New Mexico, and far west Texas; besides being found in Sonora, Chihuahua and Durango of the Occidental cordillera, a large species locale occurs to the east in Nuevo León.
Tidestromia lanuginosa, commonly known as woolly tidestromia, woolly honeysweet, honeysweet, or honeymat in English and as hierba lanuda, hierba ceniza, or espanta vaqueras in Spanish, is a species of plant in the family Amaranthaceae. It is a low growing annual found in the United States, Mexico, and the Dominican Republic.
The Trail of the Ancients is a collection of National Scenic Byways located in the U.S. Four Corners states of Utah, Colorado, New Mexico, and Arizona. These byways comprise:
Quercus grisea, commonly known as the gray oak, shin oak or scrub oak, is a North American species deciduous or evergreen shrub or medium-sized tree in the white oak group. It is native to the mountains of the southwestern United States and northern Mexico. It hybridises with four other oak species where the ranges overlap, the Arizona white oak (Q. arizonica), the Gambel oak (Q. gambelii), the Mohr oak (Q. mohriana) and the sandpaper oak (Q. pungens).
Artemisia carruthii, common name Carruth's sagewort or Carruth wormwood, is a North American species of shrubs in the daisy family native to much of south-central and southwestern United States. There are reports of a few naturalized populations in Missouri, the Great Lakes Region, and Rhode Island. It is also native to the States of Chihuahua and Sonora in northern Mexico.
Cosmos parviflorus, also known as southwestern cosmos, is a species of plant in the family Asteraceae found in North America. In many places it is a common weed in agricultural fields, although it also grows in grassy meadows in forested areas. The species appears to be native in Texas, New Mexico, Colorado, Arizona, and Utah. Collections have also been made from Massachusetts, Maine, Maryland, Missouri, Rhode Island, although it appears to be introduced to those regions. It is widespread in Mexico from Chihuahua to Oaxaca.
Xanthisma paradoxum is a plant species native to the "Four Corners" region where Colorado, Arizona, New Mexico, and Utah meet. It is known only Montezuma County (Colorado), San Juan County (Utah), and Apache County (Arizona). The species is named for the Town of Paradox, Colorado, where the type specimen was collected. It grows in disturbed sites, washes, desert scrub, and open pinyon-juniper woodlands.
Eriogonum zionis, common name Zion wild buckwheat or Point Sublime wild buckwheat, is a plant species native to the southwestern United States, the states of Utah and Arizona. It grows on sandy or gravelly soil at elevations of 1300–2300 m.
Erigeron pulcherrimus is a North American species of flowering plant in the family Asteraceae known by the common name basin fleabane. The species grows in the western United States in the eastern part of the Intermountain Region west of the Rocky Mountains. It has been found in Wyoming, Colorado, Utah, New Mexico, and Arizona.
The Indigenous peoples of the North American Southwest are those in the current states of Colorado, Arizona, New Mexico, Utah, and Nevada in the western United States, and the states of Sonora and Chihuahua in northern Mexico. An often quoted statement from Erik Reed (1666) defined the Greater Southwest culture area as extending north to south from Durango, Mexico to Durango, Colorado and east to west from Las Vegas, Nevada to Las Vegas, New Mexico. Other names sometimes used to define the region include "American Southwest", "Northern Mexico", "Chichimeca", and "Oasisamerica/Aridoamerica". This region has long been occupied by hunter-gatherers and agricultural people.
