Justo Daract (1804–1887) was an Argentine politician who served as governor of San Luis Province and in the Argentine Senate and Argentine Chamber of Deputies, representing that province.
Son of a French Argentine immigrant, Daract was born in San Luis, Argentina, studied in Buenos Aires, and became a retailer. The alliance in 1840 of Córdoba and five smaller, northwestern provinces in a Northern Coalition against Buenos Aires Province Governor Juan Manuel de Rosas (the paramount figure in the Argentine Confederation) prompted Daract to join the Unitarian Party. Following the coalition's defeat in November, however, Daract fled to Chile, and reopened his former Buenos Aires business there. He received financial support from the governor of San Luis Province, Pablo Lucero, and stockpiled arms for an eventual return.
He returned to Argentina in 1850, and purchased a cattle ranch in San Luis Province, becoming an important supplier for the Army. He was named Civil Court magistrate in 1853, though by then, he had distanced himself from Governor Lucero, and led an alliance of both Unitarians and their enemies, the Federalists, against the governor. The alliance succeeded in persuading Lucero to step down, and on November 8, 1854, Daract was selected governor by an assembly. He enacted a new provincial constitution, and promptly called for elections. Daract won in the polls later that year, and became the first elected governor of San Luis.