Sierra Madre Occidental

mountain range, North America

Also known as: Western Sierra Madre

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July 13, 2026

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The Sierra Madre Occidental is a mountain range located in northwestern Mexico, running parallel to the Pacific coast. This extensive range is part of the larger Sierra Madre mountain system, which also includes the Sierra Madre Oriental and Sierra Madre del Sur.12

Geologically, the Sierra Madre Occidental is characterized by complex structural history, with uplifted and folded strata from the Mesozoic Era. Significant lava and ash deposits from the Cenozoic Era are also present. The range features formidable escarpments and deep canyons, some comparable in scale to the Grand Canyon, such as the Barranca del Cobre (Copper Canyon).2

The climate varies with elevation, featuring distinct vertical zones from hot to cold lands. The mountains significantly influence precipitation patterns, with eastern slopes receiving more rainfall than the drier western Pacific slopes. The region supports diverse plant and animal life, though forests have been reduced by human activity. Historically, the Sierra Madre Occidental served as a refuge for indigenous peoples and continues to be a source of water for oases and agricultural districts.2

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Mexico
Physiographic regions
The largely volcanic Sierra Madre Occidental, which forms the western border of the Mexican Plateau, has an average elevation of 8,000–9,000 feet (2,400–2,700 metres) and extends roughly 700 miles (1,100 km) from north to south. It has been highly incised by westward-flowing streams that have formed a series…
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The largely volcanic Sierra Madre Occidental, which forms the western border of the Mexican Plateau, has an average elevation of 8,000–9,000 feet (2,400–2,700 metres) and extends roughly 700 miles (1,100 km) from north to south. It has been highly incised by westward-flowing streams that have formed a series…
Read More

Sierra Madre
It consists of the Sierra Madre Occidental (to the west), the Sierra Madre Oriental (to the east), and the Sierra Madre del Sur (to the south). These ranges enclose the great central Mexican Plateau, which itself is a part of the system—although the northern portion of the plateau also…
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It consists of the Sierra Madre Occidental (to the west), the Sierra Madre Oriental (to the east), and the Sierra Madre del Sur (to the south). These ranges enclose the great central Mexican Plateau, which itself is a part of the system—although the northern portion of the plateau also…
Read More