There are four of them, possibly five, depending on who is counting and when they last looked. They are sub-rectangular or D-shaped, meaning they have one curved side and one roughly straight side, and they survive not as standing walls but as depressions in the ground, their outlines traced by collapsed stonework. The largest sits against the inner face of the enclosing wall and measures just 2.25 metres by 1.6 metres internally, at a depth of around 1.2 metres. A companion structure abuts the outside of the same wall, a little north of the southern entrance, with its own low walling still surviving to about 0.4 metres. A third depression, also D-shaped and lying to the south of that entrance, may not be ancient at all; it has been tentatively identified as a relatively recent sheep-shelter.

The uncertainty over how many structures there actually are goes back at least as far as 1899, when P.J. Lynch published a plan of the fort that clearly showed a fifth structure, positioned to the south of the southern entrance and abutting the outside of the promontory wall. When Judith Cuppage surveyed the site in 1986, published in her archaeological survey of the Dingle Peninsula, she noted four or five structures but her accompanying figure showed only four. Lynch's earlier plan appears to account for the discrepancy, capturing a structure that either was missed in the later survey or had become sufficiently degraded to escape notice. Matching the structures on the ground to those shown in the two plans, and then reconciling both with Cuppage's precise measurements, has proven difficult enough that a careful physical inspection of the site is considered necessary before any firm identifications can be made.