History of the American Southwest
Most descriptions of the American Southwest mention just Arizona and New Mexico, but it's much more than that. In the United States, the American Southwest lies north of Mexico (and at one time was part of Mexico). The area is not all desert; in fact, there are many mountainous areas with pine trees, canyons that run the gamut of temperate zones, and of course coastal areas of Southern California. But just a few miles from those areas, you can find yourself back in the desert, in the more traditional sense.
There are some differences in climate and terrain. The mountain areas are cool and experience precipitation for example, while the low-lying desert areas are very hot and dry, but there is a common history that binds the American Southwest.
The Clovis people were one of the earliest groups of migrants to the area, settling nearly 13,000 years ago. They vanished three millennia later. Groups that came afterward had more stability, using agriculture as their base for the long-lasting establishment of their societies. Some of these Native American tribes in the Southwest included the Apache, Navajo, Hopi, and the Ute, which is where the state of Utah got its name. Corn became the cornerstone of the Native American diet and allowed their societies to multiply.
The 16th century brought Spanish colonization of the American Southwest; Spain also dominated much of the areas that are now Mexico. Dubbed "New Spain", it was desired to be an important part of the Spanish Economy with a wealth of precious metals. The Spanish language still dominates the Southwest with geographical names like Rio Grande, Las Cruces, San Antonio, and El Paso.
By the early 19th century, Mexico had declared their independence from Spain, and the Spanish grip loosened. Beginning in the 1820s, settlers from the United States began living in the part of Mexico that would become Texas. Over time, they fought with the government of Mexico and formed the Republic of Texas. The United States eventually annexed the Republic of Texas, which started a war with Mexico for control of what is now the majority of the American Southwest. After the war the U.S. negotiated to receive lands that became the states we know as New Mexico, Arizona, Nevada, Utah, and Colorado, along with other lands. The final boundary line was established with the Gadsden Purchase in 1854.