Ihuatzio is an archeological site in Michoacán state, Mexico. It is at the southern slopes of Cerro Tariaqueri, just north of the Ihuatzio town, in the Tzintzuntzan municipality. The ancient site is some 7 kilometers south-east of Tzintzuntzan, on the south-eastern shore of the Lake Pátzcuaro. Human settlements vestiges are registered from two different occupational periods; the first occurred between 900 and 1200 CE, corresponding to Nahuatl language speaking groups; the second group corresponding to the maximum development reached by the Purépecha Culture, between 1200 and 1530 CE. This archaeological site was built on an artificially leveled plateau, and it is considered very important, for the Michoacán prehispanic history, it was an astronomical observatory and ceremonial center. Although it is relatively small, the pyramids dedicated to "Curicaueri" and "Xaratanga" are remarkable. A sculpture representing a chac-mool (characteristic of the Toltec culture) was found; as well as a series of roads and walls surrounding the site. The prehispanic settlement fully covers a low-lying plateau and kept a strategic location at the extreme west of the lake and other dominant sites as Tzintzuntzan. According to the archeological evidence, there has been human habitation within the territory of Michoacán state for at least 10,000 years. In prehispanic times there were a number of migration waves into the area including the Pirinda, Nahua, Huetamo, Colima, Purépecha and other peoples. There are sites of formal settlements from all Mesoamerican period. Important sites include El Opeño and those in Curutarán, Tepalcatepec Apatzingán, Zinapécuaro and Coalcoman. The territory has been inhabited by the Nahuas, Otomis, Matlatzincas, Pirindas and Tecos as well as the Purépecha. The main prehispanic civilization of the state is that of the Purépecha, which was centered in the Lake Pátzcuaro area. Before the 13th century, both Nahua and Purépecha peoples were here, sustaining themselves by agriculture and fishing.