Portmarnock (Irish: Port Mearnóg) is a coastal suburban settlement in Fingal, Ireland, with significant beaches, a modest commercial core and inland residential estates, and two golf courses, including one of Ireland’s best-known golf clubs.
Portmarnock is also a civil parish in the ancient barony of Coolock in the historic County Dublin. In the 2002 census the population was 8,975 and by 2011 had climbed to 9,285.