Historedia
AmericasEvent

Anglo-French blockade of the Río de la Plata is formally declared

When
1845
Where
Buenos Aires
Episodes
1

The Anglo-French blockade of the Río de la Plata was formally declared on 18 September 1845. This naval action, imposed by the Royal Navy and French Navy, aimed to support the Colorado Party in Uruguay's civil war and resulted in the closure of Buenos Aires to maritime commerce. The blockade targeted the Argentine Confederation, led by Juan Manuel de Rosas, who refused to withdraw support for the Uruguayan White Party.

Episodes

  1. 18 September 1845 · Buenos AiresFormal Declaration of the Blockade

    The Anglo-French blockade was formally declared on 18 September 1845, closing Buenos Aires to maritime commerce.

Background and detail

Background. The blockade was a five-year naval action imposed by France and the United Kingdom on the Argentine Confederation during the Uruguayan Civil War. It was specifically designed to support the Colorado Party in Uruguay. The Argentine government, led by Juan Manuel de Rosas, resisted the blockade by maintaining support for the Uruguayan White Party, which fueled Argentina's resistance to the naval restrictions.

Formal Declaration. The blockade was formally declared on 18 September 1845. Prior to this, an ultimatum was issued by Arana, Deffaudis, and Ouseley, threatening to blockade Buenos Aires if the army of Oribe and the Argentine navy did not leave Uruguay within ten days. The declaration resulted in the closure of Buenos Aires to maritime commerce.

Argentine Resistance. Juan Manuel de Rosas resisted the blockade longer than France estimated. His strategy involved generating disputes between France and England. Additionally, Rosas included a petition signed by 15,000 British and French residents in Buenos Aires protesting the blockade. The blockade failed to bring the Argentine government to the negotiating table, frustrating the British Parliament.

People involved

  • Juan Manuel de Rosas · Leader of the Argentine government resisting the blockade
  • Arana, Deffaudis, and Ouseley · Issued the ultimatum leading to the blockade
  • William Brown · Commander of the Argentine navy whose return to Buenos Aires was permitted on condition of delivering British and French sailors, and whose British sailors were barred from sailing under the Argentine flag

Sources

  1. Anglo-French blockade of the Río de la Plata Wikipedia, revision of 2026-09-13
  2. Buenos Aires Wikipedia, revision of 2026-09-15

Machine-drafted from the cited Wikipedia passages and checked by a reviewing model, not by a human editor. Every passage cites the revision it was written from; dates and places follow those passages.