The name alone suggests the kind of deep-rooted local memory that academic classification rarely captures. The monument is classified as a possible ringfort, one of the most common early medieval site types in Ireland, typically a circular enclosure defined by a bank and ditch that once surrounded a farmstead or the residence of a person of some local standing. What makes Ballinavaun quietly puzzling is what it seems to lack: there is no surviving internal bank, and the interior sits in a distinctly dished profile, lower in the middle than at the edges, which may point to past quarrying rather than the original earthwork form.

The enclosure measures approximately 53.7 metres east to west, placing it at a reasonable size for the type. It is defined by a flat-bottomed fosse, that is, a surrounding ditch, two to three metres wide and up to around two and a half metres deep on the interior side. By the time the first edition Ordnance Survey six-inch map was produced in 1840, part of the monument had already been lost. A field boundary running north to south through the eastern quadrant divided the site, and the portion lying to the east of that boundary had been levelled entirely, leaving no visible trace at ground level. The 1840 map indicates this partial loss, which means the damage is at least that old and possibly older. What survives today is effectively the western half of what was once a complete circuit.