city, capital of Tucumán provincia(province), northwestern Argentina. It lies along the Salí River, at the foot of the scenic Aconquija Mountains. It was founded in 1565 by the Spanish colonial governor Diego de Villarroel at Ibatín on the Tejar River (now Pueblo Viejo on the Pueblo Viejo River, a tributary of the Salí). After several floods, one disastrous, in 1850, the capital was moved to its present location some 60 miles (96 km) northeast, upstream on the Salí and away from its banks. The city occupied a key position on the route from Córdoba to the Spanish silver mines in Bolivia and conducted a thriving wagon and harness trade; it was also a centre of a livestock industry that supplied draft animals for the mines of Peru. In 1776, with the creation of the viceroyalty of La Plata, control of Tucumán passed from Peru to Buenos Aires. On Sept. 24, 1812, Gen. Manuel Belgrano's forces decisively defeated Spanish royalist troops just north of the city. On July 9, 1816, a convention of delegates from the United Provinces of the Río de la Plata met at San Miguel de Tucumán and signed the declaration of independence from Spain.

The arrival of railways (1876) and the introduction of sugarcane cultivation in the early 19th century stimulated the city's commercial growth. Sugar has remained the economic mainstay, but, in an effort to diversify the economy, the government of Pres. Juan Carlos Onganía (1966–70) closed several of the sugar mills and constructed new industries. Because of its strong labour unions, Tucumán province was the scene of severe repression during Argentina's Guerra Sucia (“Dirty War”) from 1976 to 1983.

The city is known as the “garden of the republic” because of its mild climate and rich flora, and tourism has become an important source of income. Notable landmarks include the house of Bishop Colombres (who introduced sugarcane to the area), the colonial cathedral, the Casa de Gobierno (Government House, site of the independence convention), and various museums. The National University of Tucumán was established in 1914. Pop. (2001) 527,150.