Much of the region was once the Tarapacá Province of Peru, which was annexed by Chile under the 1883 Treaty of Ancón at the close of the War of the Pacific. The region was important economically as a site of intense saltpetermining, before synthetic nitrate manufacturing became possible. A number of abandoned mining towns can still be found in the region.
The present day Tarapacá Region was created in 2007 by subdividing the former Tarapacá Region under Law 20.175, which was signed by PresidentMichelle Bachelet in Arica.
A desert climate dominates the region. Near the coast, cloudiness can limit the temperature swing throughout the day, but in other drier areas, temperatures can vary greatly as is typical in deserts. A marginal desert region can be found over 3,000 m (9,843 ft) above sea level, which sees milder temperatures and summer rains.