The Cordillera Occidental of Bolivia, or Western Cordillera, forms the dramatic volcanic western edge of the Bolivian Andes. Rising above the Altiplano near the border with Chile, this high, dry mountain region contains enormous stratovolcanoes, lava fields, salt basins, geothermal features, wetlands, and some of the most remote landscapes in South America.
Its greatest summit is Nevado Sajama, which rises to 6,542 meters (21,463 feet) and is both the highest mountain in the Cordillera Occidental and the highest point in Bolivia.
Unlike many mountain ranges dominated by folded or uplifted sedimentary rock, much of Bolivia’s Cordillera Occidental is volcanic. Massive cones such as Sajama, Parinacota, Pomerape, and Acotango rise thousands of meters above an already elevated plateau, creating one of the defining landscapes of the Central Andes.
🏔️ Overview
The Cordillera Occidental forms the western mountain belt of Bolivia’s Andes. It lies primarily along the country’s frontier with Chile and borders the Altiplano on the east.
The range is part of the much larger Andes mountain system, which stretches along the western side of South America from Venezuela and Colombia to the southern tip of the continent.
In Bolivia, the Andes are especially broad. Three major geographical regions dominate the western highlands:
- Cordillera Occidental — the volcanic western mountain belt.
- Altiplano — the immense high plateau between the major cordilleras.
- Cordillera Oriental — the eastern mountain belt, which includes ranges such as the Cordillera Real.
The Cordillera Occidental is not a single continuous ridge. Instead, it consists of volcanic massifs, high ridges, plateaus, isolated cones, lava fields, basins, and mountain groups spread across a vast high-altitude landscape.
Its northern portion includes the great volcanoes surrounding Sajama National Park, while farther south the terrain becomes increasingly arid as the mountains approach the salt flats and volcanic deserts of southwestern Bolivia.
⚡ Fast Facts
| Fact | Details |
|---|---|
| Continent | South America |
| Country | Bolivia |
| Major Departments | La Paz, Oruro, and Potosí |
| Parent Mountain System | Andes |
| Andean Region | Central Andes |
| Highest Mountain | Nevado Sajama |
| Highest Elevation | 6,542 m / 21,463 ft |
| Dominant Mountain Type | Volcanic mountains and stratovolcanoes |
| Major Volcanic Region | Central Volcanic Zone of the Andes |
| Major Landscape | Altiplano |
| International Boundary | Much of the range follows or approaches the Bolivia–Chile border |
| Notable Peaks | Sajama, Parinacota, Pomerape, Acotango, Ollagüe, Licancabur |
| Important Protected Area | Sajama National Park |
| Characteristic Ecosystems | Dry puna grasslands, bofedales, high-Andean wetlands, Polylepis woodland |
| Notable Wildlife | Vicuña, Andean condor, Andean fox, Andean cat, suri |
| Popular Activities | Hiking, volcano climbing, wildlife watching, photography, cultural tourism |
📍 Where Is the Cordillera Occidental?
The Bolivian Cordillera Occidental follows the western side of the country, running roughly parallel to the border with Chile.
To its east lies the Altiplano, one of the world’s great high plateaus. Much of the Altiplano stands between approximately 3,600 and 4,200 meters above sea level, meaning that even the valleys and plains surrounding the Cordillera Occidental are extraordinarily high by ordinary mountain standards.
The northern part of the Bolivian range is dominated by the volcanoes around Sajama National Park. Farther south, the mountains continue through increasingly dry volcanic terrain toward the great salt basins and desert landscapes of Potosí Department.
The range belongs to the wider Central Andes, where the Andes reach some of their greatest width.
Rather than separating fertile lowlands, the Cordillera Occidental rises from an already high landscape. Volcanoes frequently begin from bases more than 4,000 meters above sea level before climbing another 1,000 to 2,500 meters toward their summits.
This geography helps give the region its enormous sense of scale.
🌋 A Range Built by Volcanoes
Volcanism is one of the defining characteristics of the Cordillera Occidental.
The western side of the Central Andes forms part of the Andean volcanic arc, created by the interaction of the Nazca and South American tectonic plates.
The oceanic Nazca Plate descends beneath the South American Plate along the western edge of the continent. This subduction has contributed to crustal shortening, uplift, earthquakes, and the formation of the enormous volcanic systems that dominate portions of Peru, Bolivia, Chile, and Argentina.
Western Bolivia lies within the Central Volcanic Zone, one of the principal active volcanic belts of the Andes.
Over millions of years, repeated eruptions produced:
- Stratovolcanoes
- Lava domes
- Lava flows
- Volcanic plateaus
- Calderas
- Pyroclastic deposits
- Ash layers
- Geothermal areas
- Hot springs
Some volcanoes in the region are deeply eroded remnants of ancient activity, while others retain remarkably symmetrical cones.
Volcanic activity is also responsible for many of the mineral-rich landscapes that characterize southwestern Bolivia.
🏔️ Nevado Sajama — The Highest Mountain in Bolivia
The dominant summit of the Cordillera Occidental is Nevado Sajama.
Sajama reaches 6,542 meters (21,463 feet), making it:
- The highest mountain in Bolivia
- The highest point in the Cordillera Occidental of Bolivia
- One of the major 6,000-meter volcanoes of the Central Andes
- An ultra-prominent mountain
The enormous stratovolcano rises approximately 20 kilometers east of the Chilean border.
Its broad volcanic cone stands dramatically above the surrounding Altiplano, making Sajama appear particularly massive despite the high elevation of its base.
The Smithsonian Global Volcanism Program describes Sajama as an andesitic stratovolcano constructed above older andesitic-to-rhyodacitic lava domes.
No confirmed Holocene eruption is known.
Today, ice and snow remain around its summit, although the mountain’s glaciers are remnants of much more extensive past glaciation.
⛰️ Other Major Volcanoes and Peaks
Although Sajama dominates the range, several other major volcanoes help define Bolivia’s western mountains.
Parinacota
Parinacota rises to approximately 6,348 meters (20,827 feet) on the Bolivia–Chile frontier.
Its almost perfectly symmetrical volcanic cone makes it one of the most visually distinctive mountains of the Central Andes.
Parinacota is paired with nearby Pomerape to form the Nevados de Payachata.
Pomerape
Pomerape rises to approximately 6,222 meters (20,413 feet) beside Parinacota.
The two mountains appear as enormous twin volcanoes when viewed across the Altiplano.
Pomerape is older and more heavily eroded than its neighboring volcanic cone.
Acotango
Acotango reaches 6,052 meters (19,856 feet) on the border between Bolivia and Chile.
It belongs to the Nevados de Quimsachata volcanic group and is sometimes considered one of the more approachable 6,000-meter climbing objectives in the Andes.
That reputation is relative. Extreme altitude, cold, strong winds, snow, and remote access still make Acotango a serious mountaineering objective.
Licancabur
Farther south, Licancabur rises above the exceptionally arid landscapes near the Bolivia–Chile border.
Its steep, symmetrical cone is one of the most recognizable volcanic landmarks of the Atacama–Altiplano region.
Licancabur is especially notable for the small crater lake near its summit and the archaeological remains associated with pre-Columbian use of the mountain.
🏜️ The Altiplano and High Desert Landscape
The Cordillera Occidental cannot be understood separately from the Altiplano.
The Altiplano is an enormous intermontane plateau enclosed broadly by the western and eastern Andes.
In northern and central Bolivia, it includes grasslands, lakes, wetlands, farming areas, towns, and broad plains. Conditions become progressively more arid toward the south.
Near the Cordillera Occidental, the landscape may include:
- Bare volcanic slopes
- High grasslands
- Gravel plains
- Salt basins
- Bofedales
- Lagoons
- Lava fields
- Geothermal springs
- Isolated volcanic cones
Farther south, this terrain merges into some of the driest high-elevation landscapes in the world.
The enormous Salar de Uyuni lies east of parts of the southwestern volcanic highlands. Numerous additional salt flats, shallow lakes, and mineral-rich basins occupy the surrounding plateau.
🌿 Flora of the Cordillera Occidental
Although western Bolivia can appear almost barren, specialized plants survive under extremely difficult conditions.
High elevation brings low temperatures, intense solar radiation, strong winds, limited moisture, and large temperature swings between day and night.
Queñua Woodlands
One of the most remarkable plant communities occurs around Sajama.
High-altitude Polylepis, locally known as queñua or kheñua, forms woodland on volcanic slopes where few trees can survive.
These twisted, slow-growing trees are exceptionally well adapted to cold, exposed Andean conditions.
Yareta
Yareta, or Azorella compacta, forms dense green cushion-like masses among rocks at high elevations.
Individual plants grow extremely slowly and can become very old.
Their compact structure helps conserve heat and moisture while protecting the plant against wind.
Puna Grasslands
Hardy grasses dominate many areas of the Altiplano.
These grasslands provide important grazing habitat for wild vicuñas as well as domesticated llamas and alpacas.
Bofedales
Bofedales are high-altitude wetlands created where groundwater and streams keep the soil permanently or seasonally saturated.
Despite occupying relatively small areas, these wetlands are exceptionally important sources of food and water for wildlife and livestock.
🦙 Wildlife
Animal life in the Cordillera Occidental is adapted to cold temperatures, low oxygen levels, powerful sunlight, strong winds, and limited vegetation.
Among the characteristic animals of the region are:
Vicuña
The vicuña is one of the most recognizable wild animals of the high Andes.
Closely related to llamas and alpacas, vicuñas live in open puna grasslands and are especially well adapted to high elevation.
Sajama National Park is an important area for their conservation.
Andean Condor
The Andean condor can sometimes be seen soaring above cliffs, ridges, and volcanic valleys.
Its enormous wings allow it to use rising air currents to travel great distances while expending relatively little energy.
Suri
The suri, or Darwin’s rhea, is a large flightless bird inhabiting puna and high-desert environments.
Populations are threatened in parts of their range, making protected high-Andean habitat particularly important.
Andean Cat
The elusive Andean cat is one of the rarest wild cats in the Americas.
It inhabits rocky, high-elevation environments and is rarely observed.
Other Wildlife
Additional animals found within suitable habitat include:
- Andean foxes
- Viscachas
- Flamingos
- Giant coots
- Puna ibis
- Ducks
- Hummingbirds
- Numerous other high-Andean birds
Wildlife is often concentrated near wetlands and lakes where water and vegetation are most abundant.
🌲 Sajama National Park
Sajama National Park protects one of the most important landscapes in the Cordillera Occidental.
Established in 1939, it was Bolivia’s first national protected area.
The park contains Nevado Sajama as well as volcanic mountains, high-altitude wetlands, grasslands, geothermal features, hot springs, and important queñua woodland.
Bolivia’s National Service of Protected Areas highlights several important ecosystems and species within the park, including:
- Queñua forests
- Bofedales
- Vicuñas
- Suris
- Andean cats
The park also includes a rich cultural landscape containing archaeological and historic features.
Sajama has been included on Bolivia’s UNESCO World Heritage Tentative List since 2003.
🏺 Cultural Heritage
People have lived within the high Andes for thousands of years, and the Cordillera Occidental is not simply an uninhabited wilderness.
Aymara communities have long used the Altiplano for herding, agriculture, trade, and settlement.
Mountains also hold important cultural and spiritual meaning throughout the Andes.
Within Sajama National Park and neighboring areas are numerous reminders of the region’s long human history.
UNESCO notes cultural features including:
- Pre-Hispanic burial towers known as chullpas
- Cave paintings
- Pucaras, or fortified sites
- Colonial churches
- Historic architecture
- Traditional settlements
Llamas and alpacas remain important to pastoral communities, while wetlands and high grasslands provide essential grazing areas.
The relationship between people and the mountain environment has therefore shaped the Cordillera Occidental for many centuries.
🥾 Hiking and Climbing
The Cordillera Occidental offers everything from relatively short walks around wetlands and geothermal areas to serious expeditions on 6,000-meter volcanoes.
Sajama National Park Hiking
Many visitors explore the lower landscapes surrounding Sajama rather than attempting a major summit.
Walking routes may visit:
- Hot springs
- Geyser fields
- Bofedales
- Queñua woodland
- Lagoons
- Traditional villages
- Viewpoints beneath Sajama and the Payachata volcanoes
Even these apparently gentle walks take place at elevations commonly exceeding 4,000 meters.
Climbing Nevado Sajama
Climbing Nevado Sajama is a mountaineering expedition rather than an ordinary hike.
The normal route involves high-altitude snow and glacier travel. Climbers need adequate acclimatization, appropriate equipment, knowledge of current mountain conditions, and experience with high-elevation environments.
Climbing Acotango
Acotango has gained a reputation as one of the more accessible 6,000-meter mountains in Bolivia because vehicle tracks can sometimes reach unusually high elevations.
The mountain should not be underestimated.
At more than 6,000 meters, atmospheric oxygen availability is dramatically lower than at sea level, and cold, wind, snow, ice, and rapid weather changes can create serious problems.
🏔️ Field Guide Tip: Do not judge hiking difficulty in the Cordillera Occidental by distance alone. A five-kilometer walk above 4,500 meters can be considerably more demanding than a much longer route at low elevation. Build time into your itinerary for acclimatization before attempting strenuous hikes or climbs.
🌤️ Best Time to Visit
The most popular period for hiking and mountaineering in western Bolivia is generally during the drier austral winter months, roughly May through September.
These months often provide clearer skies and more stable conditions than the summer wet season.
However, winter also brings:
- Very cold nights
- Strong winds
- Subfreezing temperatures
- Snow and ice at higher elevations
- Severe wind chill
The wetter season generally occurs during the austral summer, especially from December through March.
Afternoon storms, snow at elevation, cloud cover, and difficult road conditions may become more common.
Weather can change quickly at any time of year.
⚠️ High-Altitude Safety
Altitude is one of the greatest hazards in the Cordillera Occidental.
Many visitor destinations begin above 4,000 meters, while major summits rise beyond 6,000 meters.
Travelers arriving directly from low elevation should avoid immediately undertaking strenuous activity.
Potential warning signs of altitude illness include:
- Headache
- Nausea
- Dizziness
- Unusual fatigue
- Poor coordination
- Difficulty sleeping
- Shortness of breath
Worsening symptoms should never be ignored.
Remote roads and limited emergency services add another layer of risk. Travelers should carry appropriate food, water, navigation equipment, sun protection, warm clothing, first-aid supplies, and emergency equipment.
Review The Ten Essentials for Hiking before heading into remote mountain terrain.
🧊 Glaciers and Past Glaciation
The highest volcanoes of Bolivia’s Cordillera Occidental retain areas of permanent snow and ice.
Nevado Sajama is the most important example.
The modern glaciers are much smaller than the ice that covered portions of these mountains during colder periods of the Pleistocene.
Older glaciers carved and modified volcanic slopes, while moraines and other glacial deposits record former ice extent.
Because the region is exceptionally dry, extensive modern glaciers are difficult to maintain even at very high elevations.
The combination of ancient volcanic landforms and later glacial erosion has produced many of the rugged landscapes visible today.
🧭 Nearby Natural Attractions
The Cordillera Occidental borders several of the most spectacular landscapes in the Central Andes.
Salar de Uyuni
The enormous Salar de Uyuni is the world’s largest salt flat and one of Bolivia’s best-known natural attractions.
Its vast white surface occupies a closed basin of the southern Altiplano.
Lake Chungará
On the Chilean side of the border, Lake Chungará lies beneath the Payachata volcanoes.
Parinacota and Pomerape form an extraordinary backdrop above the lake.
Lauca National Park
Chile’s Lauca National Park borders the high volcanic landscape near Bolivia’s Sajama region.
It protects volcanoes, lakes, wetlands, and important populations of high-Andean wildlife.
Eduardo Avaroa Reserve
Farther south, southwestern Bolivia contains the Eduardo Avaroa Andean Fauna National Reserve.
Its volcanic and high-desert landscapes include colorful lagoons, flamingo habitat, geothermal areas, salt basins, and exceptionally barren mountain terrain.
💡 Fun Facts
- Nevado Sajama is the highest mountain in Bolivia, reaching 6,542 meters.
- Much of the Cordillera Occidental is volcanic rather than being a single continuous rocky ridge.
- The range forms the western side of Bolivia’s enormous Altiplano.
- Sajama National Park was Bolivia’s first national protected area.
- Parinacota and Pomerape form the striking twin volcanoes known as the Payachata.
- Some volcanoes in the range rise more than 6,000 meters despite beginning from terrain already higher than many famous mountain summits elsewhere in the world.
- High-altitude Polylepis trees survive on slopes where environmental conditions prevent most other trees from growing.
- Bofedales provide some of the most important wildlife habitat in an otherwise extremely dry landscape.
- The region forms part of the Central Volcanic Zone of the Andes.
- Volcanoes, salt flats, wetlands, glaciers, geysers, and high desert can all occur within the same broad mountain region.
❓ Frequently Asked Questions
Where is the Cordillera Occidental in Bolivia?
The Cordillera Occidental forms the western mountain belt of Bolivia’s Andes. It runs near and along much of the country’s border with Chile, with the Altiplano lying immediately to the east.
What is the highest mountain in the Cordillera Occidental of Bolivia?
Nevado Sajama is the highest mountain in the Bolivian Cordillera Occidental at 6,542 meters (21,463 feet). It is also the highest mountain in Bolivia.
Is the Cordillera Occidental part of the Andes?
Yes. It is one of the major western divisions of the Central Andes.
Is the Cordillera Occidental volcanic?
Much of Bolivia’s Cordillera Occidental is dominated by volcanic terrain. Large stratovolcanoes, lava flows, volcanic plateaus, geothermal areas, and ancient volcanic complexes occur throughout the region.
What are the most famous mountains in the Cordillera Occidental?
Important mountains include Nevado Sajama, Parinacota, Pomerape, Acotango, Ollagüe, and Licancabur.
Can you hike in the Cordillera Occidental?
Yes. Sajama National Park offers hiking and sightseeing opportunities, while major peaks attract experienced mountaineers.
Even lower-level hikes frequently occur above 4,000 meters, so acclimatization is extremely important.
What wildlife lives in the Cordillera Occidental?
Wildlife includes vicuñas, Andean foxes, viscachas, Andean condors, suris, flamingos, Andean cats, and numerous high-altitude birds.
When is the best time to visit?
For hiking and mountaineering, the drier period from approximately May through September is generally preferred. Conditions at high elevation can remain extremely cold and windy even during this season.
🔗 Related Articles
- Nevado Sajama
- Acotango
- Licancabur
- The Central Andes
- Map of the Andes Mountain Range
- Mountains in South America
- The World’s Top 100 Mountain Ranges
🔗 Related Hiking and Safety Guides
📚 Sources
- Smithsonian Institution — Global Volcanism Program: Nevado del Sajama — volcanic structure and elevation of Nevado Sajama.
- Smithsonian Institution — Global Volcanism Program: Volcanoes of Bolivia — volcanic geography, Parinacota, Pomerape, Sajama, and other Bolivian volcanic centers.
- Servicio Nacional de Áreas Protegidas de Bolivia — Parque Nacional Sajama — Sajama National Park history, ecosystems, wildlife, and conservation.
- UNESCO World Heritage Centre — Sajama National Park — natural and cultural heritage of Sajama National Park.
- U.S. Geological Survey — Satellite Image Atlas of Glaciers of the World: South America — glaciers and high-mountain environments of the Andes, including Bolivia’s Cordillera Occidental.
