PORTRUSH, a seaport and the most popular seaside resort of Co. Antrim, Ireland; the terminus of a branch of the Northern Counties (Midland) railway. Pop. (1901), 1941. It is very picturesquely situated on the basaltic peninsula of Ramore Head, with a deep bay on either side, and a harbour protected by the natural breakwater known as the Skerries. A fine hotel, owned by the railway company, and an excellent golf course are the chief features, together with a town-hall with public reading room, and the place is much frequented for golf and sea-bathing. It is also the centre for visitors to the Giants' Causeway, with which it is connected by an electric railway. Dunluce Castle, between Portrush and Bushmills, stands on a rock separated from the mainland by a chasm which is spanned by a bridge. The ruins, which are extensive, are of unknown date. Portrush has a thriving trade in salmon. It is governed by an urban district council.