Siege of Uruguaiana

Battle of Uruguaiana
Part of the Paraguayan War
Paraguayan surrender
Date August–September, 1865 Location Uruguaiana, Brazil Result Allied victory, Paraguayan surrender on 18 September
Belligerents
Paraguay Paraguayan Army Paraguayan Navy	Empire of Brazil Imperial Army Imperial Navy Argentina Argentine Army Uruguay Uruguayan Army
Commanders and leaders
Col. Estigarribia	Pedro II Conde d'Eu Bartolomé Mitre Flores
Strength
8,000 men 8 Cannons	12,330 Brazilians 3,800 Argentines 1,220 Uruguaians 54 cannons 6 steamers (Imperial Navy)
Casualties and losses
3,000 casualties 5,000 captured (surrender)	unknown

The Siege of Uruguaiana was an engagement in the Paraguayan War that began in late August, 1865, and ended on the 18th of September that year when the Paraguayans were forced to surrender due to low food supplies, despite President López's order to the Paraguayan commander, Colonel Estigarribia, not to do so. After the allied victory at Uruguaiana, Lopéz withdrew his army from Argentina and Brazil.

On July 16, the Brazilian Army reached the border of Rio Grande do Sul and soon surrounded Uruguaiana. The troop received reinforcements and sent at least three subpoenas to surrender to Estigarribia. On September 11, emperor Pedro II arrived at the scene of the siege, where there were the presidents of Argentina Bartolomé Mitre and Uruguay Venancio Flores and several military leaders, as Admiral Tamandaré. The allied forces of the siege counted on 17,346 combatants and 12,393 Brazilians, Argentine 3,802 and 1,220 Uruguayans, and 54 guns. The surrender came on September 16 when Estigarribia entered into an agreement regarding the conditions.

The Paraguayan Army had captured Uruguaiana at 5 August 1865, without any resistance.