A long narrow strip of land (no more than c.265 mi/430 km wide) between the Andes and the Pacific Ocean, Chile stretches c.2,880 mi (4,630 km) from near lat. 18°S to Cape Horn (lat. 56°S), including at its southern end the Strait of Magellan and Tierra del Fuego, an island shared with Argentina. In the Pacific Ocean are Chile's several island possessions, including Easter Island, the Juan Fernández islands, and the Diego Ramírez islands. Chile also claims a sector of Antarctica.
The country is composed of three distinct and parallel natural regions—from east to west, the Andes, the central lowlands, and the Coast Ranges. The Chilean Andes contain many high peaks and volcanoes; Ojos del Salado (22,539 ft/6,870 m high) is the second highest point in South America. Chile is located along an active zone in the earth's crust and experiences numerous earthquakes, some of great magnitude. The rivers of Chile are generally short and swift-flowing, rising in the well-watered Andean highlands and flowing generally west to the Pacific Ocean; the Loa and Baker rivers are the longest, but those in the central portion of the country are much more important because of their use for irrigation and power production.
The climate, which varies from hot desert in the north through Mediterranean-type in the central portion to the cool and humid marine west coast type in the south, is influenced by the cold Peruvian (or Humboldt) Current along the coast of N Chile and by the Andes. Precipitation increases southward; the desert in the north is practically rainless, while S Chile receives abundant precipitation throughout the year. However, along the coast of N Chile high humidity and dense fogs modify the desert climate. The Andes are an orographic barrier, and the western slopes and the peaks receive much precipitation; permanently snowcapped mountains are found along Chile's length.
In N Chile is the southern portion of the extensive desert zone of W South America. It is occupied mainly by the sun-baked Desert of Atacama, which, toward the south, gradually becomes a semiarid steppe with limited vegetation. The barren landscape of the north extends from the coast to the Andes, where snowcapped peaks tower above the desert. The Loa River is N Chile's only perennial stream. The region's scanty population is concentrated along the coast and in oases; the ports of Arica, Iquique, and Antofagasta (the chief link between Bolivia and the Pacific), the mining towns of Calama and Coplapó, and the industrial town of La Serena are the chief population centers. The people of the region are almost totally dependent on supplies from the outside. N Chile, the economic mainstay of the nation, is rich in a variety of minerals, including copper, nitrates, iron, manganese, molybdenum, gold, and silver. Chuquicamata, one of the world's largest copper-mining centers, long produced much of Chile's annual output, but the mine at Escondida now surpasses it.
The middle portion of the country, roughly between lat. 30°S and 38°S, has a Mediterranean-type climate and fertile soils, and is the nation's most populous and productive region as well as the political and cultural center. It contains Chile's largest cities—Santiago, Valparaiso (the seat of the Chilean congress), and Concepción. Mineral deposits (in particular copper, coal, and silver) are found in central Chile, and the rivers, especially the Bío-Bío, have been harnessed to generate electricity; hydroelectricity is responsible for 70% of Chile's power. The region, the most highly industrialized section of Chile, produces a large variety of manufactured products, especially in and around Santiago, Concepción, and Valparaiso (which is also Chile's chief port). Between the Andes and the Coast Ranges is the Vale of Chile, a long valley divided into basins by Andean spurs. The valley is the heart of the republic, having the highest population density and the highest agricultural and industrial output.
S Chile, extending from the Bío-Bío River to Cape Horn, is cold and humid, with dense forests, heavy rainfall, snow-covered peaks, glaciers, and islands. Sections of this region, which is in the direct path of moist westerly winds, receive more than 100 in. (254 cm) of precipitation annually. Because of subsidence of the earth's crust, the Coast Ranges and the central lowlands have been partially submerged, forming the extensive archipelago of S Chile, an area of craggy islands (notably Chiloé), numerous channels, and deep fjords. The Chilean lake district is a noted resort area. Although all of S Chile is forested, only the drier northern part has exploitable timber resources; Puerto Montt and Temuco are major timber-handling centers. The rest of the region is a wilderness of midlatitude rain forest, which has been extensively logged. Pollution and erosion have added to the environmental threat. Because of the climate, agriculture is limited; oats and potatoes are the chief crops. Livestock raising (cattle and pigs) is an important activity. A portion of extreme S Chile lies in the rain shadow of the Andes and is covered by natural grasslands; extensive sheep grazing is carried on, with wool, mutton, and skins the chief products. Cattle are also raised. This area also yields petroleum. Valdivia, a port on the Pacific Ocean, is the fourth largest industrial center of Chile; Punta Arenas on the Strait of Magellan is the world's southernmost city.