Central Mexican Plateau in the context of San Miguel de Allende, Guanajuato

León (Spanish pronunciation: [leˈon]), officially León de Los Aldama, is the most populous city and municipal seat of the municipality of León in the Mexican state of Guanajuato. In the 2020 census, INEGI reported 1,579,803 people living in the city of León and 1,721,215 in the municipality, making it the fourth-most populous city and third-most populous municipality in Mexico. The metropolitan area of León recorded a population of 2,140,094 in the 2020 state census, making it the seventh most populous metropolitan area in Mexico. León is part of the macroregion of Bajío within the Central Mexican Plateau.

León has a large leather industry, making shoes, boots, belts, jackets, and other leather accessories for national and international markets. The leather industry earned its inhabitants the nickname of "green belly" (panzaverde in Spanish) because of the green tainting in the workers' bodies resulting from treating leather. Its first-class services and hotel industry make it an important commercial center in Mexico with numerous options for entertainment, gastronomy, leisure activities, arts, and recreation. It is also considered one of the most environmentally friendly cities in Mexico and has a high number of cyclists, in part because of integrating a network of bike lanes into the SIT system. In March 2012, it received an award as "City Water Champion", mainly due to great progress in the areas of sanitation, wastewater reuse, and energy cogeneration from biogas.

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.