Tehuacán-Cuicatlán Valley, part of the Mesoamerican region, is the arid or semi-arid zone with the richest biodiversity in all of North America.

The 714,566 hectare site comprises two distinct partsthe dormant volcanic Pinacate Shield of black and red lava flows and desert pavements to the east, and,

The 56,259 ha biosphere lies within rugged forested mountains about 100 km northwest of Mexico City.