The Atacama Desert is located along the Pacific side of northern South America, principally in northern Chile and extending into southern Peru. Most descriptions place the core of the Atacama within Chile's northern regions, including areas around Antofagasta, Atacama and Tarapaca, although the precise boundaries vary. The desert lies between the Pacific Ocean to the west and the Andes Mountains to the east, with the Coastal Cordillera forming an additional major topographic feature near the coast. Its narrow north south orientation reflects the geography of the South American margin. The region is one of the driest places on Earth because its location combines cold coastal waters, subtropical atmospheric circulation and strong rain shadow effects.
In Chile, the Atacama extends through a large part of the country's northern desert zone. Major cities and settlements associated with the region include Antofagasta, Calama, Iquique and Copiapo, although not all of these lie in equally arid parts of the broader desert system. The city of San Pedro de Atacama lies farther inland near the Salar de Atacama and the high volcanic Andes. The Atacama therefore contains coastal, interior basin and high elevation environments. Elevation changes substantially from the Pacific coast to the Andes, producing differences in temperature, precipitation, vegetation and geological processes across relatively short horizontal distances.
The desert also extends into southern Peru, particularly in the extremely dry coastal desert environments around the Atacama's northern continuation. The broader Peruvian coastal desert forms part of the same climatic system influenced by the cold Humboldt Current and subtropical atmospheric circulation. The boundary between the Atacama and other Peruvian desert regions is not a simple political line or universally agreed geographical border. Desert boundaries are commonly based on climate, vegetation and geomorphology, which can produce different mapped extents. Consequently, references that restrict the Atacama to Chile and references that include parts of southern Peru can both reflect different definitions of the term.
To the west, the Atacama reaches the Pacific coastal zone. The cold Humboldt Current offshore strongly affects the climate by cooling the lower atmosphere and suppressing rainfall. In some coastal locations, fog can occur even though precipitation is extremely low. To the east, the Andes rise dramatically and create a rain shadow that limits the arrival of moist air from the Amazonian interior. The Coastal Cordillera can also block or modify the influence of marine moisture. This combination makes the Atacama an unusual desert because it lies beside an ocean but remains extraordinarily dry. Coastal proximity therefore does not automatically mean a desert will receive substantial rainfall.
The Atacama's interior includes extensive salt flats and basins. The Salar de Atacama is one of the most prominent, occupying a closed basin where evaporation concentrates salts and minerals. Surrounding landscapes include volcanoes, high plateaus, dry valleys and gravel plains. The Andes contain numerous high volcanic peaks and geothermal features. Some parts of the desert rise to considerable elevations, creating cold conditions despite the desert's tropical and subtropical latitude. The geographical transition from coastal desert to high Andean terrain means that the Atacama should not be understood as one uniform elevation or landscape.
The location of the Atacama has shaped its economic geography. Northern Chile is one of the world's major mining regions, particularly for copper, while salt flats contain lithium bearing brines and other minerals. Mining centres and transport routes connect isolated desert settlements with coastal ports and interior industrial areas. The scarcity of natural water makes infrastructure especially important. Water can come from groundwater, desalination, pipelines and other engineered systems. Mining, urban development and agriculture in adjacent valleys must therefore operate within a highly constrained water environment.
The location also explains why the Atacama is important to science. High altitude, low atmospheric moisture and extensive cloud free conditions have made northern Chile a major location for astronomical observatories. The extremely dry soils and rocks provide useful analogues for studying possible environments on Mars, while the desert's geology preserves evidence of long term climate change and hydrological conditions. Researchers study ancient groundwater, mineral deposits, salt crusts and microbial communities to understand how life and landscapes respond to extreme environmental stress.
The Atacama Desert is therefore principally located in northern Chile along the Pacific side of South America, with related and sometimes included desert environments extending into southern Peru. It lies between the Pacific Ocean and the Andes, with the Coastal Cordillera contributing to its distinctive geography. Its extreme aridity results from the combined effects of the cold Humboldt Current, subtropical high pressure and major mountain rain shadows. The region contains coastal fog zones, salt flats, rocky plains, high volcanic terrain and mining landscapes, making its geographical location important for climate science, ecology, astronomy, geology and human settlement.
