Atacama Desert (ätäkäˈmä) [key], arid region, c.600 mi (970 km) long, N Chile, extending south from the border of Peru. The desert itself, c.2,000 ft (610 m) above sea level, is a series of dry salt basins flanked on the W by the Pacific coastal range, averaging c.2,500 ft (760 m) high, and on the E by the Andes. There is practically no vegetation; rain has virtually never been recorded in some localities, and some river beds appear to have been dry for tens of thousands of years. Of the streams descending from the Andes only the Loa River reaches the Pacific. Antofagasta and other regional ports are without protected anchorages and are subject to frequent and severe earthquakes. The Atacama has been a source of great nitrate and copper wealth.
The first European to cross the forbidding waste was Diego de Almagro, the Spanish conquistador, in 1537. From then until the middle of the 19th cent. it was largely ignored, but with the discovery of the use of sodium nitrate as a fertilizer and later with the invention of smokeless powder using nitroglycerin, the desert had a mining boom. Although the southern half of Atacama belonged to Bolivia, the companies exploiting the deposits were Chilean. Differences arose, and in the ensuing war (see Pacific, War of the), Chile won the entire area. When synthetic nitrates were developed after World War I, the boom collapsed. Economically, the Atacama is declining, as reserves are depleted and the desert expands southward into once arable land.