That cluster alone is quietly remarkable; raths, the earthen-banked circular enclosures built across Ireland from roughly the early medieval period into the early centuries of the second millennium, are common enough individually, but a tight grouping like this suggests a settled, organised landscape that the present-day pasture gives little hint of.

The rath at Treanfohanaun was recorded on the 1838 Ordnance Survey six-inch map as a circular embanked enclosure somewhere between 35 and 40 metres in diameter. Two details on that map stand out. First, the word 'Caves' was marked in the north-west quadrant, almost certainly referring to a souterrain, an underground stone-lined passage or chamber associated with many raths, used variously for storage or refuge. Second, a vernacular rectangular house was already truncating the north-east edge of the enclosure, meaning the rath had been partly built over well before the first systematic mapping of the country. By the time later Ordnance Survey editions were produced, the rath itself had disappeared from the cartographic record entirely, replaced by the house and its associated field. On the ground today, the outline of the enclosure, roughly 32 metres north to south and perhaps 25 to 30 metres east to west, can still be faintly traced. It is clearest along the north-east to south-west axis, where a levelled scarp meets the natural fall of land toward the river. A shallow depression about five metres across in the southern half may indicate a souterrain still lying underground. At the south-west perimeter, field clearance stones have gathered at the base of an ash tree, and among them sits a large slab that may once have served as a lintel for that very passage. A hawthorn bush, the kind of tree long associated in Irish tradition with such enclosures, grows on the northern edge. A hollow to the north-east marks where the long-gone farmhouse once stood.