| Carnllundain | |
| Elevation M: | 136 |
| Elevation Ref: | [1] |
| Prominence M: | 136 |
| Listing: | HuMP[2] |
| Language: | Welsh |
| Location: | St David's Head, Wales |
| Map: | Wales Pembrokeshire |
| Label Position: | bottom |
| Coordinates: | 51.862°N -5.3476°W |
| Grid Ref Uk: | SM6961123460 |
| Type: | rhyolite |
| Age: | Cretaceous[3] |
| First Ascent: | ancestral |
| Easiest Route: | Hike |
Carnllundain or Carn Llundain is the highest elevation of Ramsey Island in Pembrokeshire, Wales.[4]
The 1360NaN0 high hill stands near the west coast of Ramsey island. The top of the hill is marked by a large cairn and a trig point.[5] On clear days it offers a view of a long stretch of Pembrokeshire coastline, Skomer Island and, across the Irish Sea, of SW Ireland.[6]
The area surrounding the hill is of archaeological interest and hosts some Bronze Age stone wall remains.[7] Carn Llundain—along with Carn Ysgubor, located near the northern shore of Ramsey Island—during Middle Ages offered a useful landmark to seafaring pilgrims heading to St Davids.[8]
The summit of the hill can be reached with a short waymarked diversion from the trail round the island; no special hiking ability is required, but wearing proper outdoor clothing is advisable.
Carnllundain and Ramsey Island are owned and managed by the Royal Society for the Protection of Birds (RSPB).[9]