The Sierra begins at the Rio Grande at Big Bend National Park and extends southeast for about 72 kilometres (45 mi), reaching a maximum elevation of 2,720 metres (8,920 ft).

Sierra Madre Oriental endemic Pinus stylesii grows on the higher elevations, Chinquapin oak is also common although not dominant component throughout mixed conifer forest to oak-pine forest, Quaking aspen stands exist on moist slopes and canyons, thickets of Red raspberry and hawthorns such as Crataegus tracyi and Crataegus greggiana provide forage for wildlife.

Sclerophyllous temperate broad-leaved evergreen shrubland Chihuahuan Interior Chaparral: Shrubs such as Fraxinus greggii, Mohr oak and Quercus vaseyana grow along Achnatherum eminens, Agave lechuguilla, Vauquelinia corymbosa, Desert ceanothus, Alder-leaf mountain-mahogany, Smooth-leaf sotol, Muhlenbergia emersleyi, Yucca faxoniana, Muhlenbergia setifolia and Sideoats grama.

Extremely xeromorphic evergreen shrubland Chihuahuan Creosotebush Desert Scrub: Dominated by Creosote bush associated with Whitethorn acacia, Agave lechuguilla, Bouteloua ramosa, Candelilla, New Mexico rubber plant and Tiquilia hispidissima.

Temperate cold-deciduous shrubland Madrean Montane Scrub: Mainly consists of Alder-leaf mountain-mahogany and Pointleaf manzanita growing with Muhlenbergia emersleyi and Sideoats grama.

At higher elevations Bigtooth maple, American basswood, Narrowleaf cottonwood, Chisos hop-hornbeam, Scouler's willow, Texas ash and Arizona cypress.

Coming down from the mountains several streams feed the Rio Grande, lining them grow Fremont's cottonwood, Velvet ash, Desert willow and Screwbean mesquite.

[11] The Maderas del Carmen Protected Area was created in 1994, although conservation efforts were initially slowed because the land was privately owned, either in large ranches or in the collective farms called ejidos in Mexico.

In the late 1980s the corridor between the Sierra and the mountains of west Texas enabled the black bear to disperse northward and reestablish itself in Big Bend National Park.

[8] In other initiatives, in 2000, CEMEX in cooperation with conservation organizations in Mexico and Texas began breeding and releasing to the wild bighorn sheep which had been absent from the Sierra del Carmen for more than 50 years.

[8] On October 24, 2011, Mexico and the United States signed an agreement for "Cooperative Action for Conservation in the Big Bend-Rio Bravo Natural Area of Binational Interest.