The Third Siege of Gerona refers to the French Grande Armée's seven-month siege of Girona, from 6 May to 12 December 1809, a significant event in the Peninsular War. Some 18,000 French and Westphalian troops, commanded by General Laurent de Gouvion Saint-Cyr during much of the siege, before Marshal Pierre Augereau took command on 12 October besieged the town, which held out under General Mariano Alvarez de Castro, in command of some 5,600 regular troops and militiamen, until disease and famine compelled it to capitulate on 12 December.