Nevado Sajama ([neˈβaðo saˈxama]; Aymara: Chak Xaña) is an extinct volcano and the highest peak in Bolivia.

It is situated in Sajama National Park and is a composite volcano consisting of a stratovolcano on top of several lava domes.

The mountain is covered by an ice cap, and Polylepis tarapacana trees occur up to 5,000 metres (16,000 ft) elevation.

[6] In Bolivia, the Andes mountain chain splits into two branches separated by a 3,500–4,000 metres (11,500–13,100 ft) high plateau, the Altiplano.

[11] Below 4,200 metres (13,800 ft) the mountain is characterized by parasitic vents and a cover of lava fragments and volcanic ash.

[9] The terrain is characterized by a continuous ice cover in the central sector of the mountain, exposures of bedrock, deposits and rock glaciers in some sites, alluvial fans and scree in the periphery of Sajama and moraines forming a girdle around the upper sector of Sajama.

They mostly occur within glacial valleys, but some appear to have formed underneath small plateau ice caps on flatter terrain.

The southern flanks give rise to the Huaythana River, which flows directly south and then makes a sharp turn to the east.

[20] Volcanoes in the region have ages ranging from Pleistocene to Miocene[16] and grew on top of earlier ignimbrites; the whole volcanic activity was controlled by faults.

[3] The Sajama volcano rises within a caldera that has been buried by later volcanic activity so that it is only recognizable on its eastern-northeastern side.

During the southern hemisphere summer, easterly winds carry moist air towards Sajama where solar insolation then triggers showers and thunderstorms;[11] the moisture ultimately originates in the Atlantic Ocean.

[8] Summer precipitation is typically reduced during El Nino years,[33] but on Nevado Sajama there is little correlation.

[9] The trees are usually no higher than 5 metres (16 ft) and are separated by large distances from each other and appear to localize to spots where water is available.

[16] Two ice cores were taken from the summit area in 1997,[8] preceded by a religious ceremony, as the local Aymara people feared that the mountain deities would be angered by the drilling otherwise.

[46] In another local belief, Tacora and Sajama were two mountains in competition for two women (the Nevados de Payachata).

[47] There are a number of archaeological sites on the mountain, including chullpa burials and pukara fortifications, distributed over various altitudes and connected through paths.