Where are sodium nitrate deposits found?

Sodium nitrate, also known as Chile saltpetre, is found primarily in the arid regions of South America, specifically within northern Chile and parts of Peru.123

These deposits are concentrated in the Atacama Desert, particularly in the regions of Tarapacá and Antofagasta. The nitrate-bearing gravel or rock found in these areas is referred to as caliche. Historically, these deposits were found in the central depression and various basins of the coastal range, where they were systematically mined beginning in the mid-19th century.432