placenames.ie
Townland

Portmarnock

Port Mearnóg

Excavated material offers a cautious clue to the age of a prominent earthwork.

Watercolour and fine ink of the grassy bank, narrow road and flat tidal vegetation beside Portmarnock Peninsula.
The road and tidal vegetation beside Portmarnock Peninsula, looking south-west, as photographed in August 2007.
Recorded locationPortmarnock53.42081° N · 6.15043° WInteractive map supplied by OpenStreetMap.
Recorded place location · Logainm.ie

The name

portport, bank, fort

These Irish name elements are associated with this record in the Logainm glossary.

An element’s translation is a clue, rather than a complete explanation of the name. Its form and meaning depend on local history and the full Irish name.

Recorded forms

  • Port Mearnóg · Irish · main form · validated name
  • Portmarnock · English · main form

Place & story

Testing the mound

Portmarnock’s flat-topped mound is oval, measuring about 27 by 14 metres. Test trenches revealed severe modern disturbance, but some intact deposits of dumped clay survived. These contained pieces of shell, charcoal and occasional sherds of medieval pottery. The National Monuments Service records the excavator’s suggestion that the mound may therefore be medieval. This remains an interpretation of the excavated material, rather than a securely established construction date. [2]

Geographic information

Place type
Townland
County
Dublin
Barony
Coolock
Civil parish
Portmarnock
Coordinates
53.42081, -6.15043
Mapped area
1.57 km²
Logainm ID
1411866 ↗

People & family history

Census figures refer to the matched historical census area for each year. Boundaries and spellings can change over time.

Sources & further reading

  1. Logainm.ie — Portmarnock. Place names and geographic record, licensed under CC BY 4.0.
  2. DU015-014, Portmarnock mound; revised20June2023 · Geraldine Stout; revised Caimin O’Brien, National Monuments Service
  3. Boundary geometry retains its source attribution and licence in the downloadable geographic record. Map tiles © OpenStreetMap contributors.
  4. Tidal landscape beside Portmarnock Peninsula, County Dublin illustration: based on a Portmarnock Peninsula by Raymond Okonski. AI-assisted watercolour and ink adaptation; cream paper margins added, incidental clutter omitted and fine details simplified. Licence: CC BY-SA 2.0.

Name record retrieved 2026-10-25 · Source record modified 2024-06-28. How this page was prepared.