Diego de Almagro () is a Chilean city and commune in Chañaral Province, Atacama Region. The commune has an area of . The area is named after Diego de Almagro, a conquistador. Until 1977, the city was named Pueblo Hundido ("Sunk Town").
Various mines and mineral prospects lie in the commune including the copper mines of Esperanza and El Salvador and the polymetallic Santo Domingo project.
According to the 2002 census of the National Statistics Institute, Diego de Almagro had 18,589 inhabitants (10,031 men and 8,558 women). Of these, 17,674 (95.1%) lived in urban areas and 915 (4.9%) in rural areas. The population fell by 32.4-32.4% (8926 persons) between the 1992 and 2002 censuses.
As a commune, Diego de Almagro is a third-level administrative division of Chile administered by a municipal council, headed by an alcalde (mayor) who is directly elected every four years.