The Battle of Castellón was an ambush delivered against a French Imperial detachment under General Reille near Girona during the Peninsular War (1807–14). Having crept his force up along the right bank of the Fluvià River and set up headquarters at La Armentera, a village near the river's mouth on the Mediterranean Sea, General Lazán prepared a coup de main against the French battalion installed atop Castelló d'Empúries. Since bad roads precluded a night attack, Lazán moved in the early morning, and brusquely forced the French off the ridge. While Reille's troops effected a disciplined fighting withdrawal toward Rosas, the Chasseurs of Juan Clarós, acting as the vanguard for General Castro's division, circled across their path of retreat and set up a position in a grove next to the main ro