Trouillas nestles in a plain on the Canterrane stream at an altitude of about 100 meters. Mas Deu, an establishment founded by the Knights Templar in medieval times, is located 2.4 km to the east. Thuir lies five km to the northwest. Ricardos defended these positions with a force of 17,000 soldiers and 38 cannons. The second battalion of the "Barcelona" Infantry Regiment arrived, but this reinforcement did not make up for the heavy Spanish losses suffered at Peyrestortes. Dagobert attacked the Spanish defenses with 22,000 soldiers. The French order of battle included the 7th, 61st, 70th, and 79th Infantry Demi-Brigades, as well as the National Guards of Gers and Gard.