The Arica y Parinacota Region ( ) is one of Chile's 16 first order administrative divisions. It comprises two provinces, Arica and Parinacota. It borders Peru's Department of Tacna to the north, Bolivia's La Paz and Oruro departments to the east and Chile's Tarapacá Region to the south. Arica y Parinacota is the 5th smallest, the 3rd least populous and the 6th least densely populated of the regions of Chile. Arica is the region's capital and largest city. The 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. Following annexation, Arica y Parinacota went through a process of forced acculturation known as Chilenization with the aim of creating a dominance of Chilean traditions and culture. Administration In 2007, the region was subdivided to create the Arica y Parinacota region and the present day Tarapacá Region to the south. The region is further subdivided into two provinces: Arica and Parinacota. Demography According to data from the 2017 Census of the National Statistics Institute, the region is populated by 224,548 inhabitants. Its density reaches 13.3 inhabitants per km². This region holds the largest population of Aymara and a significant number of immigrants from neighboring Peru and Bolivia. Included are those of Asian descent, such as Chinese and Japanese; and Arabs from Lebanon, Palestine and Syria. Most of the country's Afro-Chileans live in the Arica province, descended from slaves in the 17th and 18th centuries. There are a large number of Roma people or Gypsies in the Arica province as well, originated from Eastern Europe in the late 19th century. At the level of cities, the most populated are: Arica, with 175,441 inhabitants and Putre, with 1235 inhabitants. Geography The region lies within the Norte Grande (Far North) natural region. It combines deserts, green valleys, the steep and volcanic Andes mountains, and the Altiplano (high plain) to the east. A narrow coastal strip of low-lying land no more than wide separates the Pacific's Nazca plate from the Andes. Its Parinacota volcano is the region's highest elevation at and lies on the northern border with Bolivia in Lauca National Park. Hydrology The region's two main rivers are the Lauca, which drains into Bolivia's Coipasa salt flat (Lago Coipasa), and the Lluta, which flows into the Pacific