The Sierra del Carmen, also called the Sierra Maderas del Carmen, is a northern finger of the Sierra Madre Oriental in the state of Coahuila, Mexico. 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). Part of the Sierra del Carmen is protected in the Maderas del Carmen Biosphere Reserve as part of a bi-national effort to conserve a large portion of the Chihuahua Desert in Mexico and Texas.