Arcos de la Frontera is a town of southern Spain, in the province of Cadiz; on the right bank of the river Guadalete, which flows past Santa Maria into the Bay of Cadiz. Pop. (1900) 13,926. The town occupies a ridge of sandstone, washed on three sides by the river, and commanding fine views of the lofty peak of San Cristobal, on the east, and the fertile Guadalete Valley, celebrated in ancient Spanish ballads for its horses. At the highest point of the ridge is a Gothic church with a fine gateway, and a modern tower overlooking the town. The fame of its ten bells dates from the wars between Spaniards and Moors in which “Arcos of the Frontier” received its name. After its capture by Alphonso the Wise of Castile (1252-1284), the town was a Christian stronghold on the borders of Moorish territory. Another church contains several Moorish banners, taken in 1483 at the battle of Zahara, a neighboring village. The ruined citadel, the theatre, and the palace of the dukes of Arcos are the only other noteworthy buildings. Roman remains have been found in the vicinity, and the ridge of Arcos is honeycombed with rock-hewn chambers, said to be ancient cave-dwellings. See Galeria de Arcobricenses illustres (Arcos, 1892), and Riqueza y culture de Arcos de la Frontera (Arcos, 1898) ; both by M. Mancheiio y Olivares.