The XV Arica and Parinacota Region is one of Chile's 15 first order administrative divisions. It borders Peru to the north, Bolivia to the east and Chile's Tarapaca Region to the south. It is also the country's newest region, created under Law 20.175. It became operational on October 8, 2007. Chile's former Tarapaca region was a former Peruvian province, which was occupied by Chile under the 1883 Treaty of Ancón at the close of the War of the Pacific, and then formally annexed in 1929 by the Treaty of Lima.
In 2007, the region was subdivided to create the Arica and Parinacota region and the present day Tarapacá Region to the south. The region is further subdivided into two provinces: Arica and Parinacota.According to data from the 2002 Census of INE, the region is populated by 189 644 inhabitants. Its density reaches 11.2 inhabitants per km ².