Rosario lies by the Paraná River, about 300 km upstream from the Argentine capital Buenos Aires; it is a major port and an industrial, commercial and cultural center.
In 1724 another colonial settlement was initiated by Santiago de Montenegro, who set up a mill, drew plans for the future town, built a chapel, and was appointed mayor in 1751.
In 1841 its port was shut off to foreign trade by a decree of the caudillo and Governor of Buenos Aires, Juan Manuel de Rosas which banned navigation of the Paraná and the Paraguay rivers to non-Argentine vessels.
On 25 December 1851, a small group of locals and the military guard of the city declared their support for the rival caudillo Justo José de Urquiza.
Governor Domingo Crespo justified the request at the provincial legislative body, marking the geographically strategic position of the town for national and international trade, and on 5 August Rosario was formally declared a city.
By 1887 it had about 50,000 inhabitants, of which 40% were immigrants, who brought new ideas from Europe and started turning Rosario into a politically progressive city (contrasting with the more conservative, aristocratic Santa Fe).
Rosario was indeed declared the federal capital in three occasions, but each time the law received a veto of the Executive Branch (once by Bartolomé Mitre and twice by Domingo Faustino Sarmiento).
Demographic growth took its toll of bad living conditions, epidemics of contagious diseases such as tuberculosis, and increased labour offer resulting in exploitation.
Rosario hosted some matches of the Football World Cup 1978, which was used by the military junta as a distraction for the populace, to cover up illegal repression and human rights abuses.
About 400,000 rosarinos attended the final campaign meeting of the Radical Civic Union, which won locally (with the election of Mayor Horacio Usandizaga) and nationally (with President Raúl Alfonsín).
In Rosario, protests against the price rises and lack of supplies, coupled with general social discontent and the influence of extremist elements, ended up in riots and looting to supermarkets and other businesses, which then spread to other large cities.
While macroeconomy was healthy and prices stabilized, after a few years of improvement the situation in Rosario turned to the worse, as the industrial sector of the city was dismantled by competition from cheap imports (favoured by the low fixed exchange rate) and the agricultural exports stagnated.
These shantytowns have always existed in modern times, but they increased in area and population during this period, often augmented by internal migration (residents of poorer regions of the country, particularly Chaco Province).
The last official survey, a study conducted by the Municipal Bank Foundation, dates from 1996; it indicated the presence of 91 precarious settlements, with 115,000 inhabitants (10% of the population of the metropolitan area).
The massive boom in agricultural exports (mainly soybean products) in the province has caused a large amount of consumer spending and investment in Rosario, which is also receiving more small-scale tourism than ever.