The 171,774.4 hectares (663.225 sq mi) reserve surrounds the volcanoes of Popocatépetl and Ixtaccíhuatl and marks the biogeographical boundary between the Nearctic and Neotropical realms.

There is a very marked ecosystem gradient deriving from the variations in altitude, favoring enormous specific wealth and the presence of endemic species.

Its diverse ecosystems consist of the pine and sacred fir (Abies religiosa, Oyamel in Nahuatl) of the Trans-Mexican Volcanic Belt pine-oak forests as well as high-mountain prairies.

[1] The transition zone is the only part with human settlements, including 31,480 inhabitants and land given over to farming, stock-raising, forestry, harvesting or other uses.

The Ecological Planning Programme for Popocatépetl volcano and its Area of Influence covers a surface area of approximately 28,319,253 hectares (109,341.25 sq mi) involving 34 municipalities in three states, namely: Ixtapaluca, Tlalmanalco, Cocotitlán, Temamatla, Tenango del Aire, Ayapango, Amecameca, Ozumba, Tepetlixpa, Atlautla and Ecatzingo, in the State of Mexico; Acteopan, Atlixco, Atzizihuacan, Calpan, Cohuecan, Chiautzingo, San Nicolás de los Ranchos, San Salvador El Verde, Santa Isabel Cholula, Tianguismanalco, Tlahuapan, Tochimilco, Domingo Arenas, Huaquechula, Huejotzingo, Nealtican, San Felipe Teotlancingo and San Jerónimo Tecuinapan, in the State of Puebla; Ocuituco, Temoac, Tetela del Volcán, Yecapixtla and Zacualpan de Amilpas in the State of Morelos.