The monument consists of an Iron Age fortification, or dun, which has been partly reconstructed. There is evidence for re-use in the latter part of the first millennium AD.
Castle Haven dun was cleared of rubble and partly reconstructed in 1905. The limit of original stonework was shown by a painted line, now obscure, and the work is commemorated by a small bronze plaque set into the walling to the left of the entrance, inside the courtyard.Artefacts recovered from the 1905 excavations include human bones, pottery, worked stone and metal artefacts of the early Iron
Age and also, possibly, of 8th/9th century AD date.
The dun is D-shaped on plan, with walls up to 5m thick surrounding a courtyard 18m by 11m. The walls are galleried, and contain at least one stone stairway, although the reconstruction of the upper levels is not necessarily authentic. The dun stands within an outer courtyard of similar plan but with narrower walls, now much reduced. There are entrances at the NE end of the dun and also to the WSW, the latter leading steeply down to a small bay, which would have provided an ideal landing place for small boats.
The area to be scheduled includes the dun, the outer enclosure and an area around them, in which evidence relating to their construction and use may survive. It is bounded to the NW by the top of a steep rocky drop. The area measures a maximum of 85m NE-SW by 40m, as marked in red on the accompanying map.
Statement of National Importance
The monument is of national importance as a very fine and generally convincing reconstruction of an Iron Age dun, in an area where such monuments are numerous but usually in a thoroughly ruined condition. Despite excavations in the early twentieth century, considerable amounts of undisturbed archaeological deposits can be expected to survive, which, taken with the foundations of the original structure preserved beneath the 1905 rebuilding work, have the potential to provide important evidence about Iron Age and early medieval defensive architecture and domestic economy.