The Olmec Heartland refers to the geographic region in modern-day southern Mexico, particularly the states of Veracruz and Tabasco, where the Olmec civilization flourished from approximately 1200 BCE to 400 BCE. This area is recognized as the cultural and political center of the Olmecs, who are often regarded as the 'mother culture' of Mesoamerica due to their significant influence on later civilizations in the region.