Narberth Castle may have been sited on the location of a pre-Norman llys and commote. In 2001 at least 20 burials, extended inhumations aligned east-west, were noted by Dyfed Archaeological Trust 30m north of the remains of Narberth Castle. It is thought that the burials are part of a much larger cemetery (NPRN 423435), and intercutting graves indicate that it was in use for a significant period of time. Pottery and a radiocarbon date indicate a 12th-13th century date for the burials. Although the current parish church lies some 60m to the west, it has been suggested that the cemetery indicates the former location of the church prior to the establishment of the castle.

The visible remains of the single ward Narberth Castle are thought to date from the mid-thirteenth century and later. They include a rectangular enclosure approximately 40m north to south by 20m with the ruins of two quarter-engaged drum towers and traces of a curtain wall with two semi-cirular bastions to the west of the enclosure. To the east is a vaulted cellar, the remains of a tower, and evidence of two garderobes.

The castle is first mentioned in 1116 and was possibly occupied until the seventeenth century. It is described in a survey of 1539.

J.Wiles, RCAHMW, 27 April 2004