Sierra Madre Occidental Sierra Madre Occidental The Sierra Madre Occidental is a major mountain range system of the North American Cordillera, that runs northwest–southeast through Northwestern and Western Mexico, and along the Gulf of California. The Sierra Madre is part of the American Cordillera, a chain of mountain ranges (cordillera) that consists of an almost continuous sequence of mountain ranges that form the western "backbone" of North America, Central America, South America and Antarctica. The Spanish name "sierra madre" means "mother mountains" and "occidental" means "western" in English, with these being the "Western Mother Mountains". To the east, from the Spanish "oriental" meaning
Arizona/New Mexico Mountains ecoregion the mountain ranges that extend eastwards into western New Mexico from the Arizona transition zone. The "White Mountains subregion" of eastern Arizona is a high altitude area extending into about ten ranges of western-(central) New Mexico, and west of the Rio Grande. East of the Rio Grande and extending southeast is a monolithic section of mountains, mostly the Sacramento Mountains but extending southeast into the Guadalupe Mountains. In the central-north, east of the Rio Grande another monolithic section is made of the Sandia-Manzanita Mountains. West of the Rio Grande extending northwest towards the Chuskas, on the Arizona-New Mexico border, are