Carreg Samson is a 5000 year old Neolithic burial chamber located ½ mile west of Abercastle overlooking the bay.
The capstone measures 15foot (4.5 m) long by 9 foot (2.75m) wide and is supported by 3 out of the 7 upright stones. When constructed, it is likely that Carreg Samson would have been covered by an earth mound, making it one of a handful of Britain's surviving portal tombs. The tomb is constructed around a central pit, filled with clay and stone.
Abercastle is off the A487 between Fishguard and St Davids.