Known as Cahergon Fort on the Ordnance Survey Fair Plan, it is technically a cashel, the term used for a ringfort defined by a stone wall rather than an earthen bank or ditch. At roughly 64 metres east to west and 51 metres north to south, it was never a modest structure, yet today it takes some attention to read it properly against the surrounding fields.

What survives is a drystone wall, now grassed over and poorly preserved, though stretches of double wall-facing remain visible in places, suggesting the original construction had some solidity to it. The southern portion has fared worst. Rubble deposited during land reclamation has been piled on top of and against the wall, and the interior's southern half has been brought into agricultural use altogether. A field wall, almost certainly much later in date, cuts across the monument at the north-east and south-west, embedding the old cashel within the working geometry of the modern farm. Only the northern half of the interior still shows traces of internal divisions, the low stone partitions that once separated different activity areas within the enclosure. A gap in the wall at the north-north-east may be an original entrance, though its condition makes certainty difficult.

Cashels of this kind are generally associated with the early medieval period in Ireland, typically the centuries between roughly 500 and 1000 AD, and they served as enclosed farmsteads for families of varying social rank. Cahergon Fort's scale places it towards the larger end of the type, though its present condition reflects centuries of practical agricultural pressure rather than deliberate excavation or investigation. The layers of disturbance, field walls threading through it, reclamation rubble banked against it, the southern interior smoothed into pasture, tell their own story about how the land has been managed long after whoever built it was forgotten.