Chālco [ˈt͡ʃaːɬko] was a complex pre-Columbian Nahua altepetl or confederacy in central Mexico.

It was divided into the four sub-altepetl of Tlalmanalco/Tlacochcalco, Amaquemecan, Tenanco Texopalco Tepopolla and Chimalhuacan-Chalco, which were themselves further subdivided into altepetl tlayacatl, each with its own tlatoani (king).

According to the Amaqueme historian Chimalpahin, this was because the Chalca refused a Mexica demand to contribute building materials for the temple of Huitzilopochtli.

[3] This was achieved, in part, by the diplomacy work carried out by the Chalcan musician Quecholcohuatl when he performed a politically-driven composition for Axayacatl in 1479.

Chalco paid more tribute to Tenochtitlan in the form of food than any other region in the Valley of Mexico, probably because of its fertile soil and location.