Mound C (Group 3)

18.4667°N, 95.4333°W.

Mound C, part of Group 3 at Tres Zapotes in southern Veracruz, Mexico, is one of the principal earthen pyramidal mounds at the late Olmec capital that succeeded San Lorenzo and La Venta. The mound was built between approximately 400 BCE and 200 CE during the Epi-Olmec period, of compacted earth and clay fill rising about 12 metres in stepped tiers. Tres Zapotes is best known as the find-spot of Stela C, which bears the earliest documented Long Count date in Mesoamerica — a partial date corresponding to 32 BCE — establishing that the Mesoamerican calendar system originated in the Gulf Coast lowlands rather than the Maya region. Matthew Stirling excavated Stela C in 1939; further investigation of Mound C and the surrounding precinct was conducted by Christopher Pool from 1995 onward.

Mound C is an earthen pyramid in the city where the Long Count calendar was first written down on a stone.