I wonder whether you had some options, but a safe answer is: Mesoamerica (that's essentially the territory of today's Mexico excluding the very north of Mexico). The Mayas were in the Yukatan Peninsula, and south of it, the Aztecs on a vast land surrounding today's Mexico City, the Olmecs "between" them and the Zapotec to the south, but what they had in common is that all were in Mesoamerica.