The Chichimeca War (1550–90) 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 driven by the Spaniards which led to the pacification and, ultimately, the streamlined integration of the native populations into the New Spain society.

The Bajío 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 the states of Querétaro, Guanajuato, parts of Jalisco, Aguascalientes and parts of Zacatecas, San Luis Potosí and Michoacán.