It is roughly circular, measuring about a hundred metres north to south and ninety-five metres east to west, and its defining feature is a substantial earthen bank still standing to an external height of around two metres. For something so sizeable, it leaves surprisingly little impression on the historical record.

Enclosures of this type, formed by a raised bank and sometimes accompanied by a fosse (a shallow external ditch dug to provide material for the bank and to reinforce its defensive or boundary function), are a familiar but still imperfectly understood feature of the Irish countryside. They range in date across several millennia and served purposes from farming and livestock management to more overtly ceremonial or territorial functions. At Kilronane, the bank is interrupted in two places: a gap to the north-north-east measuring just over three metres wide, and a wider opening to the south-west at four metres, both likely original entrances rather than later breaches. A shallow fosse survives on the eastern side. The interior remains level, offering no obvious surface clues about what activities once took place within it.