The forests extend almost continuously along the range through the states of Veracruz, Hidalgo, Querétaro, Guanajuato, San Luis Potosí, Tamaulipas, Nuevo León, and northern Puebla.

North of Monterrey, the forests become discontinuous, extending as a series of sky islands through the states of Nuevo León and Coahuila, and on into the Chisos and Davis mountains of the Big Bend region of western Texas.

Endemic species include Quercus ariifolia, Q. edwardsiae, Q. flocculenta, Q. furfuracea, Q. galeanensis, Q. hirtifolia, Q. hypoxantha, Q. miquihuanensis, Q. runcinatifolia, Q. rysophylla, Q.saltillensis, and Q. verde.

[4] Mammals that inhabit this ecoregion include the American black bear (Ursus americanus), which migrate along the Rio Grande from northern Coahuila to the Chisos Mountains in Texas, mule deer (Odocoileus hemionus), cougar (Puma concolor), cliff chipmunk (Tamias dorsalis), collared peccary (Pecari tajacu), white-nosed coati (Nasua narica), jaguar (Panthera onca) and coyote (Canis latrans).

Wild turkeys (Meleagris gallapavo), peregrine falcons (Falco peregrinus) and golden eagle (Aquila chrysaetos) are also resident.