Acozac

Acozac is a small, little-visited archaeological site on the slopes of Cerro de Moctezuma in Ixtapaluca, beside kilometre 30 of the old Mexico City–Puebla highway. Until 1973 it was known as Ixtapaluca Viejo. That year the land of the old Acozac ranch was divided up for a housing development and golf club, and the ranch's name passed to the ruins as well.

Archaeologists link the place to Tlazallan-Tlallanoztoc, which the Codex Xólotl names as the seat of Techotlalatzin, Xólotl's grandson and later ruler of Texcoco, and it lay within Acolhuacan, the kingdom centred on Texcoco. Pottery shows people here from the Aztec I phase (900 to 1200 CE) through Aztec II (1200 to 1430), the period of Techotlalatzin's reign, but the buildings you can see today belong to the final stage, between 1430 and 1521.

The standout is a round temple to Ehécatl, the wind god. Between it and the so-called Palace lies the Great Platform, a complex of rooms, patios and altars that still keeps patches of red stucco. More than a hundred structures have been detected, most of them probably houses; INAH counts 47 mounds and six platforms inside a protected area of about 28 hectares, declared a federal archaeological monuments zone in 1993. The open, tree-ringed site looks out to Popocatépetl and Iztaccíhuatl.

Research has picked up again after a long pause. In 2025 the national school of anthropology (ENAH) and INAH began mapping the site with LiDAR, with archaeological salvage work and the stabilisation of the most damaged areas planned for 2026. One of those is a platform beside the Ehécatl temple that earlier studies suggested may have been a tzompantli, or skull rack. Housing already presses against the edges of the site.