Chalcatzingo is a Mesoamerican archaeological site in the Valley of Morelos dating from the Formative Period of Mesoamerican chronology. The site is well known for its extensive array of Olmec-style monumental art and iconography. Located in the southern portion of the Central Highlands of Mexico, Chalcatzingo is estimated to have been settled as early as 1500 BCE. The inhabitants began to produce and display Olmec-style art and architecture around 900 BCE. At its height between 700 BCE and 500 BCE, Chalcatzingo's population is estimated at between five hundred and a thousand individuals. By 500 BCE it had gone into decline.
The Chalcatzingo center covers roughly . It was well-situated in a fertile plain, at the base of two tall hills, Cerro Chalcatzingo and Cerro Delgado. Cerro Chalcatzingo has evidence of long regard and use as a site of ritual significance.
The climate in Morelos is generally warmer and more humid than the rest of the Highlands. A spring rising at the base of the hills provided a source of drinking water for the population.
Chalcatzingo connected trade routes between Guerrero, the Valley of Mexico, Oaxaca, and the Gulf Lowlands.