Argentine Confederation
The State of Buenos Aires ("Estado de Buenos Ayres") was a secessionist republic resulting from the overthrow of the Argentine Confederation government in the Province of Buenos Aires on September 11, 1852. The State of Buenos Aires was never recognized by the Confederation or by foreign nations; it remained, however, nominally independent under its own government and constitution. Buenos Aires rejoined the Argentine Confederation after the former's victory at the Battle of Pavón in 1861.