Chalco is Barlow's Province 21. It is described on the page 19 of the Matrícula and on folio 41 (recto) of the Codex Mendecino.The following maps and table are all from Barlow (1949).

Location Map. Chalco is shown in green.

 
Barlow's map of the Province. Chalco overlaps three modern political boundaries, Morelos in the south, the Distrito Federal in the west, and the Estado de Mexico in the central part of the map. The two large volcanoes Iztaccihual (The White Woman) and Popocatepetl (The Smoking Mountain) lie to the east. The Chalco on this map is not the Chalco on the shore of Lake Chalco.

 

Tributary Pueblos

1. Chalco
 
2. Quauhxumulco
3. Tepuztlan
a. Amaquemacan
... Malinaltepec (not located)
... Tecmilco (not located)
... Xocoyoltepec (not located)

 

Modern Location

1. Chalco - Tlalmanalco, or Chalco - Amecameca de Juárez, Méx.*
2. Cuajomulco, Mor.
3. Tepotzlan, Mor., or Poxtla, Méx.*
 
... ?
... Tequimilco, Méx.*
... ?

Key

* Modern location from Castillo Farreras (1997). The appelidos of the modern place names are also from Castillo Farreras (1997).

? Location uncertain