Balbriggan, a market-town and seaport of Co. Dublin, Ireland, in the north parliamentary division, 21&FRAC34; m. N.N.E. of Dublin by the Great Northern railway. Pop. (1901) 2236. The harbour, though dry at low tides, has a depth of 14 ft. at high-water springs, and affords a good refuge from the east or southeast gales. There are two piers, and a railway viaduct of eleven arches crosses the harbour. The town has considerable manufactures of cottons and hosiery, "Balbriggan hose" being well known. The industry was founded by Baron Hamilton in 1761. There is some coast trade in grain, etc., and sea-fishery is prosecuted. Balbriggan is much frequented as a watering-place in summer.