Chichimeca in the context of "Codex Xolotl"

The Bajío (the Lowlands) is a cultural and geographical region within the central Mexican plateau which roughly spans from northwest of Mexico City to the main silver mines in the northern-central part of the country. This includes (from south to north) the states of Querétaro, Guanajuato, parts of Jalisco (Centro, Los Altos de Jalisco), Aguascalientes and parts of Zacatecas, San Luis Potosí and Michoacán.

Located at the border between Mesoamerica and Aridoamerica, El Bajío saw relatively few permanent settlements and big civilizations during Pre-Columbian history, being mostly inhabited by the Otomi and semi-nomadic tribes known to the Aztecs as the "Chichimeca" peoples (poorly attested conglomerate of Uto-Nahua groups, from whom the Toltec and the Aztecs were probably descended). The tribes that inhabited the Bajío proved to be some of the hardest to conquer for the Spanish—peace was ultimately achieved via truce and negotiation—but due to its strategic location in the Silver Route, it also drew prominent attention from Europe, and some of the flagship Mexican colonial cities were built there, such as Zacatecas and Guanajuato. Abundant mineral wealth and favorable farming conditions would soon turn the region into the wealthiest of New Spain. At the beginning of the 19th century, El Bajío was also the place of the ignition of the Mexican War of Independence, and saw most of its battles during the initial phase of the war, including the Cry of Dolores, the storming of the Alhóndiga de Granaditas and the Battle of Calderón Bridge.

Aguascalientes (Spanish pronunciation: [ˌaɣwaskaˈljentes] , lit. "hot waters" in Spanish) is the capital of the Mexican state of Aguascalientes and its most populous city, as well as the head of the Aguascalientes Municipality, with a population of 948,990 inhabitants in 2012 and 1,225,432 in the metro area. The metropolitan area also includes the municipalities of Jesús María and San Francisco de los Romo. It is located in North-Central Mexico, which roughly corresponds to the Bajío region within the central Mexican plateau. The city stands on a valley of steppe climate at 1880 meters above sea level, at 21°51′N 102°18′W / 21.850°N 102.300°W / 21.850; -102.300.

Originally the territory of the nomadic Chichimeca peoples, the city was founded on October 22, 1575, by Spanish families relocating from Lagos de Moreno under the name of Villa de Nuestra Señora de la Asunción de las Aguas Calientes (Village of Our Lady of the Assumption of the Hot Waters), in reference to the chosen patron saint and the many thermal springs found close to the village, which still remain to this day. It would serve as an outpost in the Silver Route, while politically, it was part of the kingdom of Nueva Galicia. In 1835, President Antonio López de Santa Anna made Aguascalientes the capital of a new territory in retaliation to the state of Zacatecas, eventually becoming capital of a new state in 1857. During the Porfiriato era, Aguascalientes was chosen to host the main workshops of the Mexican Central Railway company; bringing an industrial and cultural explosion. The city hosted the Revolutionary Convention of 1914, an important meeting of war generals during the Mexican Revolution.

The Chichimeca War (1550–1600) was a military conflict between the Spanish Empire and the Chichimeca Confederation established in the territories today known as the Central Mexican Plateau, called by the Conquistadores La Gran Chichimeca. The epicenter of the hostilities was the region now called the Bajío. The Chichimeca War is recorded as the longest and most expensive military campaign confronting the Spanish Empire and indigenous people in Aridoamerica. The forty-year conflict was settled through several peace treaties with the Spaniards which led to the pacification and, ultimately, the integration of the native populations into the New Spain society.

The Chichimeca War (1550–1600) began eight years after the two-year Mixtón War. It can be considered a continuation of the rebellion as the fighting did not come to a halt in the intervening years. The war was fought in what are the present-day Mexican states of Zacatecas, Guanajuato, Aguascalientes, Jalisco, Queretaro, and San Luis Potosí.

The north Pame, or Xi'iuy (alternate spelling: Xi'úi, Xi'ui, Xi'oi, or Xiyui), as they refer to themselves, the south Pame, or Ñáhu, Nyaxu (in Hidalgo), and the Pame in Querétaro or Re Nuye Eyyä, are an Indigenous people of central Mexico primarily living in the state of San Luis Potosí. When Spanish colonists arrived and conquered their traditional territory in the sixteenth century, which "extended from the modern state of Tamaulipas in the north to Hidalgo and the area around Mexico City in the south along the Sierra Madre," they renamed "the area Pamería, and applied the name Pame to all of the peoples there."

Estimates for population of the Pames at the time of contact with Spanish colonists in 1519 range between 40,000 and 70,000. In 1794, the population was estimated at 25,000. Recent figures for the Pame have estimated the population to be approximately 10,000 people. The Pames, along with the Chichimeca-Jonaz of the Sierra Gorda in eastern Guanajuato, are the only two intact cultural groups "of all the peoples known collectively as Chichimecas" who have survived colonization.

The Zacatecos (or Zacatecas) are an indigenous group, one of the peoples called Chichimecas by the Aztecs. They lived in most of what is now the state of Zacatecas and the northeastern part of Durango. They have many direct descendants, but most of their culture and traditions have disappeared with time. Large concentrations of modern-day descendants may reside in Zacatecas and Durango, as well as other large cities of Mexico.