Petrolina is a municipality located in the southernmost point of the state of Pernambuco, in Northeast Brazil, in the valley of the São Francisco River. The population was 354,317 in 2020, and the total area is km², making it the largest municipality in the state by area. The municipality is closely integrated with Juazeiro, Bahia, located on the opposite bank of the São Francisco. Etymology Formerly called (), there is no single story explaining the origin of the name Petrolina. One theory is that the name was in tribute of Brazilian emperor Pedro I and his consort Leopoldina, while another asserts that Petrolina was named for a 'beautiful rock' () found on the banks of the São Francisco. History The growth of Petrolina and its twin city Juazeiro in the late 20th century is the result of the construction of the Sobradinho Dam and the abundant availability of water for irrigation in these otherwise semi-arid soils. The region is perhaps the only one in the interior of the Northeast that has gained population through in-migration. While the population in the states of Pernambuco and Bahia as a whole increased by 50.1% between 1970 and 1990, it more than doubled in Petrolina-Juazeiro. For many years the economy of the Valley of the São Francisco was based on extensive cattle ranching and subsistence farming. Starting in the 1960s with the development policies implemented by the government, the valley soon became the beneficiary of important investments for economic development, translated into the construction of highways, increasing electrical energy, improvement in sanitation systems etc. Investments made in the agricultural sector with the implantation of the irrigated sections of Bebedouro and Senador Nilo Coelho, in turn brought in the installation of factories connected to the regional agriculture base, especially producers of tomato paste, juices, textiles etc. Agriculture has grown by leaps and bounds with irrigated farming being the main source of income and jobs in Petrolina. The Petrolina-Juazeiro nucleus has turned into a producer of a wide range of irrigated high-value crops, including table grapes and mangos that are sold fresh by cargo aircraft to Europe and the United States, and other crops for the domestic market, including bananas, coconuts, guavas, passion fruit, melons, industrial tomatoes, watermelons and onions, among others. Due to irrigation, growers in Petrolina-Juazeiro produce 90% of the country's exports of mangos and 30% of table grapes, displacing the states of São