The monument consists of the remains of a courtyard castle,built in the 14th-15th centuries but with subsequent additions. The landward side of the Castle, which is situated on a cliffed promontory, is protected by a man made ditch crossed by a later causeway.
Substantial sections of the courtyard wall survive to a thickness of 2m, showing 16th century modifications in response to changes in the design of artillery fortifications. The only surviving entrance is the sea gate, in the N curtain wall. The dominating feature of the Castle was the tower which provided the main residential
accommodation for the MacDonald chiefs and their retinue.
This was 4 storeys high. One wall of this survived to parapet level until the late 19th century. The lower orders of a later bartizan tower, of later date, also survived until this date. All that now survives of these elements is a vaulted basement kitchen. An additional tower was built, possibly in the 16th century, abutting the N face of the earlier and larger tower. It was probably 3 storeys high and communicated directly with the larger tower.
The upper part of this tower collapsed in 1990. The most recent building within the courtyard was built in the NW corner during the 17th century. Evidence of doorways in W and E walls, a window in the N gable and joist holes along the W wall survive. There may have been other buildings within the courtyard, although no remains are visible.
The area to be scheduled is irregular in plan, 80m N-S by 90m E-W, defined to the N by the mean high water mark of the shore, to include the castle, the outer ditch and causeway and the surrounding slopes, as marked in red on the accompanying map.