Pentre Ifan is Wales' largest and best preserved Neolithic chambered tomb of the so called portal-dolmen type.

The dolmen dates from approximately 3,500 B.C. and was used as a communal burial site. The existing stones form the portal and main chamber of the tomb, which would originally have been covered with a large stone mound about 36 m long. Some of the stones have been scattered, but at least seven are in their original position. The capstone is 5.1 m in length, and is estimated to weigh 16 tonnes. It is delicately supported by the narrow tips of three uprights. The facade surrounding the portal was built with carefully constructed dry stone walling.

In 1884 it was the first monument in Britain to become a Scheduled Ancient Monument, on the recommendation of General Pitt Rivers. Original sketches from that period are shown here.

Local folklore says that sometimes fairies, or Tylweth Teg, are seen here: they are described as 'little children in clothes like soldiers clothes and with red caps'.