The earthworks at Cloghonan were levelled roughly two or three decades before the site was recorded, and a bungalow was afterwards built immediately south of the southeastern quadrant. What survives is modest: a roughly circular enclosure measuring about 32.7 metres north to south and 36.4 metres east to west, its defining bank worn down to little more than a low swell in the ground. A ringfort, or rath, is an early medieval enclosed farmstead, typically bounded by one or more earthen banks and external ditches called fosses, and this one retains traces of both an outer fosse and an outer bank, most legible along the eastern half of the site and at the west.

The site carries an older puzzle at its centre. The present landowner recalled, as a boy, a heap of stones sitting in the middle of the enclosure, which may have been the remains of a castle. Those stones are now gone. The Ordnance Survey Letters, compiled in the nineteenth century and later published by O'Flanagan in 1930, noted an indistinct castle ruin in the southeast corner of the earthen fort, and suggested this was the structure from which the townland took its name, Cloch Othanain, meaning the Rock of Othanan. The OS writer was sceptical, however, arguing that the true Cloch Othanain was more likely the castle incorporated into what was then known as Castle Otway. The question of which ruin gave the townland its name was, it seems, already a matter of debate before the stones at Cloghonan disappeared entirely.