city, northern Chile. At 35 miles (56 km) inland from the Pacific coast in the fertile Copiapó River valley, this irrigated oasis (usually regarded as the southern limit of the Atacama Desert) in an extremely arid territory has been farmed since the pre-Inca period. The community was elevated to villa (town) status in 1744, when it became San Francisco de la Selva de Copiapó. With the discovery of gold and silver deposits in the 19th century, Copiapó became a significant mining and political centre. In 1850–51 it was connected to the port and resort of Caldera, 50 miles (80 km) northwest, by one of the first railways in South America. After a period of decline from 1875 to 1925, the town's economy was revived by the development of copper mines, and a smelter was completed in 1950 at nearby Paipote. In addition to the railway, all-weather roads connect Copiapó to Caldera and to Santiago. A road also crosses the Andes Mountains into La Rioja, Arg. Pop. (2002) 125,983.