The Sierra Madre Occidental is a mountain range in western Mexico. The name Sierra Madre means "Mother Mountains". The range extends from near the Arizona border down to the Sierra Madre del Sur. The high plateau that is formed by the range is cut by deep river valleys. This plateau is formed from volcanic rock overlying a basement of metamorphic rock.

This uplift has caused changes in weather patterns; increased rainfall occurring in the mountains has provided areas where ecosystems can form in wetter areas than surrounding land. This water-source forms watersheds that provide the arid surroundings with water that makes it possible to irrigate and farm crops. The wet ecosystems are islands of biodiversity, differing significantly from what would otherwise be a desert landscape. Oak forests are the predominant plant life and extend into the low land deserts.

This forest and canyon land provided a place for a variety of indigenous people to live, until Spanish settlers with associated Mestizos came into the area to found towns for the silver mines in the area. The major industries in the area now are agriculture and forestry, which have become contentious because of land degradation and the native population's opposition to these practices.

Sierra Madre (Spanish for "mother mountain range") may refer to one of several mountain ranges:

The Sierra Madre de Chiapas, as known in Mexico, with regional names in other countries, is a major mountain range in Central America.

Geography

The range runs northwest-southeast from the state of Chiapas in Mexico, across western Guatemala, into El Salvador and Honduras. Most of the volcanoes of Guatemala, part of the Central America Volcanic Arc, are within the range.

A narrow coastal plain lies south the range, between the Sierra Madre and the Pacific Ocean. To the north lie a series of highlands and depressions, including the Chiapas Depression, which separates the Sierra Madre from the Chiapas Plateau, the Guatemalan Highlands, and Honduras' interior highlands.

The range forms the main drainage divide between the Pacific and Atlantic river systems. On the Pacific side the distance to the sea is short, and the streams, while very numerous, are consequently small and rapid. A few of the streams of the Pacific slopes rise in the Guatemalan Highlands, and force a way through the Sierra Madre at the bottom of deep ravines. On the eastern side a number of the rivers of the Atlantic slopes attain a considerable volume and size.

The Sierra Madre Mountains is the longest mountain range in the Philippines. Running in the north-south direction from the provinces of Cagayan to the north and Quezon to the south, the mountains form the eastern backbone of Luzon Island, the largest island of the archipelago. It is bordered by the Pacific Ocean to the east. The Pacific coast of Luzon along the Sierra Madre is less developed as the lofty and continuous mountains forms a bold and an almost inaccessible shore, exposed to the full force of the northeast monsoon and the waves of the Pacific Ocean. Some of communities east of the mountain range and along the coast are so remote they are still only accessible by plane or by boat.

The Quezon Protected Landscape is situated at the southern part of the range.

Geography

The Sierra Madre is the longest mountain range in the Philippines. In the north, the range starts in the province of Cagayan and ends in the south in the province of Quezon. In the province of Nueva Vizcaya, its western tip to form the Caraballo Mountains, with which it connects with the Cordillera Central range.