The first signs of complex society in Mesoamerica were the Olmecs an ancient Pre-Columbian civilization living in the tropical lowlands of south-central Mexico, in what are roughly the modern-day states of Veracruz and Tabasco. The area is about 125 miles long and 50 miles wide (200 by 80 km), with the Coatzalcoalcos River system running through the middle. These sites include San Lorenzo Tenochtitlan, Laguna de los Cerros, Tres Zapotes, and La Venta, one of the greatest of the Olmec sites. La Venta is dated to between 1200 BCE through 400 BCE which places the major development of the city in the Middle Formative Period. Located on an island in a coastal swamp overlooking the then-active Rio Palma river, the city of La Venta probably controlled a region between the Mezcalapa and Coatzacoalcos rivers.
The Olmec domain extended from the Tuxtlas mountains in the west to the lowlands of the Chontalpa in the east, a region with significant variations in geology and ecology. Over 170 Olmec monuments have been found within the area, and eighty percent of those occur at the three largest Olmec centers, La Venta, Tabasco (38%), San Lorenzo Tenochtitlan, Veracruz (30%), and Laguna de los Cerros, Veracruz (12%).
Those three major Olmec centers are spaced from east to west across the domain so that each center could exploit, control, and provide a distinct set of natural resources valuable to the overall Olmec economy. La Venta, the eastern center, is near the rich estuaries of the coast, and also could have provided cacao, rubber, and salt. San Lorenzo, at the center of the Olmec domain, controlled the vast flood plain area of Coatzacoalcos basin and riverline trade routes.
Laguna de los Cerros, adjacent to the Tuxtlas mountains, is positioned near important sources of basalt, a stone needed to manufacture manos, metates, and monuments. Perhaps marriage alliances between Olmec centers helped maintain such an exchange network.
The Olmec heartland is an archaeological term used to describe an area in the Gulf lowlands that is generally considered the birthplace of the Olmec culture. This area is characterized by swampy lowlands punctuated by low hills, ridges, and volcanoes. The Tuxtlas Mountains rise sharply in the north, along the Gulf of Mexico’s Bay of Campeche. Here the Olmecs constructed permanent city-temple complexes at San Lorenzo Tenochtitlan, La Venta, Tres Zapotes, and Laguna de los Cerros. In this region, the first Mesoamerican civilization would emerge and reign from 1400-400 BCE.
The Olmec flourished during Mesoamerica’s Formative period, dating roughly from 1400 BCE to about 400 BCE. As the first Mesoamerican civilization, they laid much of the foundation for the civilizations that would follow. Their influence went beyond the heartland – from Chalcatzingo, far to the west in the highlands of Mexico, to Izapa, on the Pacific coast near what is now Guatemala, Olmec goods have been found throughout Mesoamerica during this period.