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← 1850 1849 1848 1851 in Argentina → 1852 1853 1854
Decades:	1830s 1840s 1850s 1860s 1870s
See also:	Other events of 1851 List of years in Argentina

Events in the year 1851 in Argentina.

• Governor of Buenos Aires Province: Juan Manuel de Rosas (de facto Head of State of Argentina)
• Governor of Cordoba: Manuel López
• Governor of Santa Fe Province: Pascual Echagüe then Domingo Crespo

• May 1 – governors Justo José de Urquiza of Entre Rios and Benjamin Virasoro of Corrientes rise up against Rosas
• May 29 – Corrientes and Entre Rios enter into alliance with Uruguay and Empire of Brazil
• August 18 – Rosas declares war on Empire of Brazil

• March 19 – Roque Sáenz Peña, President 1910–1914 (d. 1914)^[1]