Chile is the narrow Pacific country of southern South America, stretching about 4,270 km from the Peruvian border at latitude 17° S to Cape Horn at 56° S while averaging only 177 km across. It covers 756,102 km², including Easter Island and Isla Salas y Gómez, and is usually divided into five natural regions: the desert Far North (Norte Grande), the semi-arid Near North (Norte Chico), Mediterranean Central Chile, the rainy Lake District of the South, and the fjords and ice fields of the Far South. Three parallel strips run through most of it: the Andes on the east, the Chilean Coast Range on the west and the Central Valley between them. The highest point is Ojos del Salado, 6,893 m (22,615 ft), the highest volcano on Earth; the longest river is the Loa, 440 km, and the Biobío, at 380 km, is the second longest and the widest.
Behind that shape is plate tectonics. The northern two-thirds of the country sit above the Nazca Plate, which slides eastward under South America at about ten centimetres a year. The collision raised the Andes, which hold about 620 volcanoes on the Chilean side, and opened the Peru–Chile Trench offshore, more than 8,000 m deep. It makes Chile highly earthquake-prone: the 1960 Valdivia earthquake, placed by most studies at magnitude 9.4 to 9.6, is the strongest ever recorded, and the 2010 Maule earthquake reached 8.8. Roughly 80 percent of the land is mountainous. To the east, the boundary with Argentina runs 5,308 km along the Andean crest and across Tierra del Fuego, the longest border in South America.
Norte Grande: The Atacama, the Altiplano and the Loa
The Far North runs from the Peruvian border to about 27° S, a line close to the Copiapó River, and is almost entirely the Atacama Desert. The Atacama covers about 105,000 km² along a 1,600 km strip west of the Andes and is the driest non-polar desert in the world, with average rainfall of around 15 mm a year; some weather stations there have never recorded rain. The Coast Range blocks Pacific moisture, the Andes block it from the Amazon side, and the cold Humboldt Current holds an inversion over the coast.
From the sea the land rises almost vertically, often to more than 1,000 m. The Coast Range here reaches its own highest point, 3,114 m at Sierra Vicuña Mackenna in the Antofagasta Region. Sea fog trapped against these bluffs is the only regular moisture many coastal plants receive. Inland, rolling hills hold the driest ground of all, where tamarugo forests once drew on aquifers until most were cut for smelter fuel.
The Far North is the only part of Chile that includes a broad piece of the Andean plateau, the Altiplano, above 4,000 m. Summer storms there, the so-called "Bolivian winter", fill shallow saline lakes and salt flats such as the Salar de Atacama, the largest in Chile, which lies 55 km south of San Pedro de Atacama between the main Andean chain and the Cordillera Domeyko. A line of volcanoes rises on its eastern rim, including Licancabur and Láscar, one of the country's most active. Lithium was found in its brines in 1962, and since the 2000s it has become a major lithium-mining hub.
A few rivers escape the plateau and cross the desert. The Loa rises at the foot of Miño Volcano near Ollagüe above 4,000 m, flows south, bends west and then north, and reaches the Pacific in a U-shaped course of 440 km. It drains the largest basin in Chile yet carries little water, and its oases are islands of green. The copper of the Sierra del Medio beside its upper valley feeds Chuquicamata, one of the largest open-pit copper mines in the world.
Norte Chico: Transverse Valleys from the Copiapó to the Aconcagua
Between the Copiapó River and about 32° S, just north of Santiago, the Andes and the Coast Range lose their clean parallel lines. Spurs run from the mountains to the sea, and the land breaks into a sequence of deep east–west Transverse Valleys. Winter rain averages about 25 mm in each of the four wet months in the centre of the region, and snowmelt keeps the rivers flowing all year, though the flow swings with the seasons and drought is common.
Ojos del Salado stands on the border at the northern edge of this zone, east of Copiapó. Its summit is a cluster of lava domes and craters with little ice; even so, a crater lake about 100 m across at roughly 6,480 to 6,500 m is the highest lake of any kind on Earth. Downslope, the irrigated valley floors grow grapes for pisco, nearly all of which is made in the Norte Chico, and table fruit for export.
Central Chile: The Central Valley between Santiago and the Biobío
From 32° S to 37° S the three-strip pattern is at its clearest. The Coast Range on the west, the high Andes on the east and the Central Valley, or Intermediate Depression, between them hold the three largest urban areas, Santiago, Valparaíso and Concepción, and most of the population. The climate is Mediterranean: Santiago averages about 19.5 °C in January and February with almost no rain, and receives 69.7 mm a month in June and July. Rainfall rises steadily southward. Concepción, near the mouth of the Biobío, gets about 253 mm a month in mid-winter.
Santiago sits in its own basin on the Mapocho River (see our guide to Santiago as Chile's capital), with the Andes rising to more than 6,000 m behind it. Across the border, about 15 km into Argentina, Aconcagua reaches 6,967 m, the highest mountain outside Asia, and the river named after it drains the Chilean side. Their snowmelt waters the northern Central Valley, Chile's richest farmland and the base of its wine and fruit exports.
The Biobío marks the southern edge of the region. It leaves Icalma and Galletué lakes in the Andes and runs 380 km to the Gulf of Arauco, averaging about a kilometre wide. Its basin is Chile's third largest, after the Loa and the Baker. South of it, the Cordillera de Nahuelbuta, a tall block of the Coast Range, keeps large tracts of old-growth forest.
The Lake District: Volcanoes and Moraine Lakes from Temuco to Chiloé
South of the Biobío, between about 37° S and the Chacao Channel at 42° S, the Central Valley sinks closer to sea level and the rivers coming off the Andes pool into large lakes before they reach the ocean. These are glacial lakes, dammed by moraines that piedmont glaciers left at the end of the last ice age, which Chilean geologists call the Llanquihue glaciation after the biggest of them. Lake Llanquihue covers about 871 km², the second-largest lake in Chile after the shared General Carrera.
Above the lakes stands a chain of snow-capped stratovolcanoes. Villarrica, 750 km south of Santiago, is one of the most active in the country and one of the few in the world with a lava lake in its crater; its eruptions of 1964 and 1971 sent lahars down its flanks. Further south, the near-perfect cone of Osorno rises over the eastern shore of Llanquihue, facing the town of Puerto Varas.
This is one of the rainiest places on Earth. Valdivia receives about 2,535 mm a year, with more than 400 mm in each of June and July. The rivers that drain the lakes, especially the Calle-Calle past Valdivia, are among the very few in Chile navigable for any distance. At the southern end, the Central Valley finally drops below the sea and becomes the Gulf of Ancud. Chiloé Island, 8,394 km² and the second largest island in Chile after Isla Grande de Tierra del Fuego, is the last high block of the Coast Range: rolling farmland in the northeast, a wild coast of forest and swamp in the southwest.
Chilean Patagonia: Fjords, the Ice Fields and the Strait of Magellan
From 42° S to Cape Horn, the Far South is a drowned landscape. The Coast Range breaks into a multitude of islands, the Central Valley lies under the sea, and the Andes descend straight into a maze of channels and fjords. Puerto Aisén averages more than 200 mm of rain a month even in summer. Further inland, General Carrera Lake, shared with Argentina where it is called Lake Buenos Aires, drains west through the Baker, Chile's largest river by volume, whose turquoise water carries glacial silt to the Pacific near Caleta Tortel.
Two great ice fields survive from the Patagonian Ice Sheet. The Northern Patagonian Ice Field, about 4,200 km², lies wholly inside Laguna San Rafael National Park and sends its San Rafael and San Quintín glaciers almost to sea level. The Southern Patagonian Ice Field, about 16,480 km² across some 350 km, is the second largest contiguous ice field outside the polar regions, and roughly 14,200 km² of it lies in Chile. Its largest western outflow, the Pío XI or Brüggen Glacier, about 66 km long, is the longest glacier in the Southern Hemisphere outside Antarctica. Our guide to the glaciers of Patagonia follows them in detail.
East of the ice, the granite horns of the Cordillera Paine rise over Torres del Paine National Park. The highest of them, Cerro Paine Grande, reaches 2,884 m. Beyond, the land flattens into the windswept steppe around Punta Arenas, the southernmost city of Chile, which gets only about 438 mm of rain a year because the Andes shelter it. The Strait of Magellan cuts through here, linking the Atlantic and Pacific; oil and gas come from its shores, and the islands of Tierra del Fuego lead south to Cape Horn and the Diego Ramírez Islands.
Rapa Nui and Juan Fernández: Chile's Pacific Islands
Chilean territory reaches deep into Polynesia. Easter Island, or Rapa Nui, lies about 3,600 km west of the mainland port of Caldera, just below the Tropic of Capricorn, and is a volcanic island known for its 867 moai statues carved from volcanic stone. The westernmost point of the country is the islet of Motu Nui, just off its coast. The Juan Fernández Islands lie 587 km west of Valparaíso, and the tiny Desventuradas and Salas y Gómez complete the outer chain. These scattered islands, together with the long mainland coast of 6,435 km, give Chile an exclusive economic zone of about 3.65 million km², nearly five times its land area.
Every region of Chile, from salt flat to glacier, is shaped by the same two forces: the subducting Nazca Plate and the cold Humboldt Current. For how they play out season by season, continue with our guide to the climate of Chile, or go deeper into its driest corner with the geography of the Atacama Desert.