Atotonilco de Tula

"Place where the water boils" is how the municipality itself translates Atotonilco, from atl, water, totonqui, hot, and co, inside; "de Tula" was added to set it apart from other Atotonilcos, given how close it is to Tula de Allende. Before Nahuatl came Otomí names: the town council lists Bathejé, Boxfi and Batha as the first settlements, built of adobe, wood and maguey leaves, and in Otomí the town is known as Padehe. According to the Codex Boturini, the Mexica passed through Atltotonquico on their migration and stayed five years before moving on toward Apazco.

The colonial founding has a date: in 1553 Fernando Fabián Cortés Tlazintlali asked Viceroy Luis de Velasco to found the town of Santiago de Atotonilco, promising to build a church and public buildings. The plateresque parish of Santiago Apóstol, linked to the Augustinians, dates from 1609 and belongs to the Diocese of Tula; the civic square lies beside it. The municipality was formally recognised by decree in 1920, within the Tula district.

The town, with 8,822 residents in 2020, sits at 2,157 metres in rolling hills with a dry temperate climate, about 17 °C on average and rain from May to September. It is part of the Tula metropolitan area; in the municipality almost 39% of workers are in industry and 56% in services, and five weekly street markets set up. On 160 hectares of its land stands the Atotonilco Wastewater Treatment Plant, designed to treat 23,000 litres per second on average and up to 35,000 in the rainy season.