The Sierra Madre Occidental is a mountain range in western Mexico and the extreme southwest of the United States, extending 1500 km from southeast Arizona (south and east of Tucson) southeast through eastern Sonora, western Chihuahua, Durango, Zacatecas, Aguascalientes to Guanajuato, where it joins with the Sierra Madre Oriental and the Eje Volcánico Transversal of central Mexico.

The highest point is probably Cerro Mohinora , located at . Different sources cite its altitude as either 3250 m or 3300 m. However, other mountains at 26°03′ N 106°25′ W and 23°12′ N 104°57′ W are of very similar altitude and may possibly be higher.

The range is noted for its high biodiversity and large number of endemic species.

See also: Madrean pine-oak woodlands

External link

• Sierra Madre Occidental pine-oak woodlands (World Wildlife Fund)