ARKLOW, urban district, Co. Wicklow, Ireland, 49m. S. of Dublin, by the Great Southern railway. Pop. (1926) 4,526. There are oyster-beds on the coast, but the oysters require to be freed from a peculiar flavour by the purer waters of the Welsh and English coast before they are fit for consumption. Copper and lead from the Vale of Avoca are shipped from the port. There are cordite and explosives works. In 1882 an act provided for improvement of the harbour and appointment of harbour commissioners. There are slight ruins of an ancient castle of the Ormondes, demolished in 1649 by Cromwell.