Portmarnock
| Portmarnock Irish: Port Mearnóg | |
|---|---|
| Suburb (village core) | |
| Portmarnock, Dublin | |
| Coordinates: 53°25′18″N 6°08′14″W / 53.4217°N 6.1372°W | |
| Country | Ireland | 
| Province | Leinster | 
| County | Dublin | 
| Local government area | Fingal | 
| Elevation | 3 m (10 ft) | 
| Population  (2022) | 10,750 | 
| Eircode routing key | D13 | 
Portmarnock (Irish: Port Mearnóg) is a coastal town in County Dublin, Ireland, north of the city of Dublin, with significant beaches, a modest commercial core and inland residential estates, and two golf courses, including one of Ireland's best-known golf clubs. As of 2022, the population was 10,750, an increase of 13.5% on the 2016 census figure of 9,466.
Portmarnock is also a civil parish in the ancient barony of Coolock. It is in the local government area of Fingal.