Concepción del Uruguay (kōnsĕpsēōˈn dĕl ōrōgwĪˈ) [key], city (1991 pop. 55,942), Entre Ríos prov., NE Argentina, a port on the Uruguay River. It produces tea, dairy products, frozen meat, and cider. It ships the grain and beef of the surrounding region to Uruguay and elsewhere. The city was founded in 1783 and was twice the capital of Argentina in the 19th cent. It was the scene of a revolt (1870) that culminated in the assassination of ex-president Justo José de Urquiza.