Ancient Monuments

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Promontory Fort on Great Castle Head

A Scheduled Monument in St. Ishmael's (Llanisan-yn-Rhos), Pembrokeshire (Sir Benfro)

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Latitude: 51.7116 / 51°42'41"N

Longitude: -5.1162 / 5°6'58"W

OS Eastings: 184812

OS Northings: 206031

OS Grid: SM848060

Mapcode National: GBR G4.G8DH

Mapcode Global: VH1RX.87MP

Entry Name: Promontory Fort on Great Castle Head

Scheduled Date: 7 February 1983

Source: Cadw

Source ID: 2082

Cadw Legacy ID: PE416

Schedule Class: Defence

Category: Promontory Fort - coastal

Period: Prehistoric

County: Pembrokeshire (Sir Benfro)

Community: St. Ishmael's (Llanisan-yn-Rhos)

Traditional County: Pembrokeshire


The monument comprises a well-preserved coastal promontory fort, probably dating from the Iron Age period (800 BC - 74 AD). It is located at the S end of a headland, which projects S into Milford Haven. The fort is defended by steep natural cliffs on the E, S and W sides. The N side of the fort is defended by a single E-W aligned bank and ditch that runs across the neck of the headland. The bank measures 150m in length and is well preserved, except for a gap on the W side where the access road has cut through. The bank ends abruptly on the E side some way short of the edge and may have been disturbed here, although this may be the site of the entrance. The outer ditch is for the most part invisible. A lighthouse compound is situated towards the W edge of the interior and is excluded from the scheduled area.

The monument is of national importance for its potential to enhance our knowledge of Iron Age settlement and social organisation. The monument forms an important element within the wider later prehistoric landscape. The structure itself may be expected to contain archaeological information in regard to chronology, building techniques and functional detail.

The area scheduled comprises the remains described and an area around within which related evidence may be expected to survive. It is an irregular polygon in shape and measures 290m E-W by 220m transversely.

Source: Cadw

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