Pular is a massive stratovolcano located in the Antofagasta Region of northern Chile, about 15 km west of the border with Argentina, which in this area is a straight line between the summits of Socompa volcano and Cerro del Rincón. Pular, along with Cerro Pajonales, forms a high volcanic ridge, which runs in a generally north-east to south-west direction for 12 km (7 mi). Southward, following the same direction as the ridge, lies Socompa volcano. The ridge's crest forms a drainage divide between Salar de Atacama basin and Salar de Pular basin. This latter is a bowl-shaped basin enclosed on the east by Aracar volcano.