Corbelling is an ancient building technique in which each course of stone projects slightly inward over the one below, gradually closing the roof without any mortar or timber to hold it together. That five such structures survive in reasonable condition within a single enclosure makes Cathair Deargáin Thuaidh quietly remarkable, even by the standards of a peninsula that has no shortage of early medieval remains.

The site is a cashel, a type of stone-walled enclosure common in early medieval Ireland, typically associated with a farmstead or small settlement of the period. Within its roughly circular boundary sit five clochans, as these corbelled drystone huts are known, all circular or sub-circular in plan. The easternmost measures 4.5 metres in diameter internally, with walls up to 1.2 metres high and between 1.5 and 2 metres thick. Its doorway faces north-west and widens slightly from the inside out, a feature known as external splaying, which helps shed rainwater away from the threshold. More intriguing still is a possible souterrain associated with this hut. A souterrain is an underground or semi-underground passage, usually drystone-lined, thought to have served for storage, refuge, or both. Here, the passage runs partly through the thickness of the hut wall before emerging at the surface to the north, though it extends only 0.9 metres before being blocked. Whether it was always this short or was once longer is not clear. The site as a whole also contains one or possibly two further souterrains. It sits on a west-north-west facing slope with open views across much of the northern side of this end of the peninsula, a position that would have made practical sense for anyone keeping watch over the surrounding landscape.