The Atacama Desert ecoregion, as defined by the World Wide Fund for Nature (WWF), extends from a few kilometers south of the Peru–Chile border to about 30° south latitude. To the north lies the Peruvian Sechura Desert ecoregion, whilst to the south is the Chilean Matorral ecoregion.
The National Geographic Society, by contrast, considers the coastal area of southern Peru to be part of the Atacama Desert. It includes in this definition the deserts south of the Ica Region in Peru.
To the east lies the less arid Central Andean dry puna ecoregion. The drier portion of this ecoregion is located south of the Loa River between the parallel Sierra Vicuña Mackenna and Cordillera Domeyko. To the north of the Loa lies the Pampa del Tamarugal.
The Atacama Desert is commonly known as the driest place in the world, especially surroundings of the abandoned Yungay town (in Antofagasta Region, Chile). The average rainfall in the Chilean region of the Atacama Desert is .004 inches per year. Meaning it gets 4 inches of rain in a thousand years. Some weather stations in the Atacama have never received rain. Periods of up to four years have been registered with no rainfall in the central sector, delimited by the cities of Antofagasta, Calama and Copiapó, in Chile. Evidence suggests that the Atacama may not have had any significant rainfall from 1570 to 1971. It is so arid that mountains that reach as high as 6,885 metres (22,589 ft) are completely free of glaciers and, in the southern part from 25°S to 27°S, may...