port, seaside resort, and urban district on the Irish Sea coast, in County Wicklow, southeast Ireland. In 431 St. Palladius, the Christian missionary, landed at the present site of Arklow. The Vikings had a settlement there, and the town was granted by John of England (John) (then the lord of Ireland) in 1189 to Theobald Fitz-Walter, lord butler of Ireland. It was an English stronghold during the late medieval period, and there are remains of a 13th-century Dominican friary and fragments of the Butler castle. Small boats, pottery, and fertilizers are manufactured there. Pop. (2006) 11,712.