San Diego de la Unión

San Diego de la Unión was first called Pueblo de Bizcocho, after a nearby hill shaped like that bread roll. Residents disliked the name, so the neighboring hacienda became San Juan Pan de Arriba, the town was for a while Pan de Abajo, and in the end it took the name of its patron, Saint Didacus of Alcalá. The official founding date is 30 November 1719, by the military commander Manuel María de Torres, though the parish archive holds a baptism from 1685 and lawsuits over the San Diego del Bizcocho hacienda go back to 1648. Today the town has 7,946 people (2020) and stands at 2,070 m in the semi-desert of northern Guanajuato, with short, cold winters.

On 3 September 1817 the insurgent troops of Francisco Xavier Mina defeated the royalists here; the town was burned and almost destroyed, and rebuilding began in 1819 on the orders of the intendant of San Luis Potosí. It became a villa on 4 May 1875. On 26 September 1917 it was the seat of the state government: that day General Celestino Gasca was sworn in as governor before the state Congress, and San Diego served as the provisional capital.

The municipality is dotted with old hacienda buildings. La Noria de Alday, 3 km southeast, was built in 1825 and keeps a Mudéjar-style courtyard with a central fountain. San Juan Pan de Arriba, 5 km away, bred fighting bulls and had the first artificial insemination lab for bravo cattle; today it makes moles and borrachita cactus-fruit jam. Tuna wine is distilled at La Jaula, and La Sauceda and Ojo Ciego sit along Highway 57.

The food is semi-desert food: colonche, a fermented drink of red cardona prickly pears served at fiestas; chancaquillas made of piloncillo with pumpkin seeds and nuts; and bolillo bread still baked in wood-fired ovens in several villages. San Diego was the most awarded municipality at the 2023 state traditional cooking contest. On Sundays, trade spills out onto the main streets.