The shape is what gives it away: a D-shaped enclosure, roughly 25.5 metres from north to south and around 15 metres east to west, its flat grass interior set off from the surrounding land by a low scarp. This is a ringfort, or at least a partial one. Ringforts, which are enclosed farmstead sites typically dating from the early medieval period, are among the most common archaeological monuments in Ireland, but their ubiquity does not make any individual example less interesting. This one, however, is somewhat reduced.

What survives at Creenagh is the western arc of what was once a more complete enclosure. Along that western side, an earthen bank still runs, modest in height but measurable, with a width of around 1.5 metres at its broadest. Beyond it, an outer fosse, the term for the defensive or boundary ditch that typically accompanied such a bank, can be traced by a band of rushes, which tend to colonise low, damp ground where a filled-in ditch has altered drainage patterns over the centuries. That rush-filled arc runs from south, around the west, and back up to the north. The eastern portion of the monument, by contrast, has been removed entirely, likely through agricultural activity over generations. What remains is essentially half a fort, enough to read the original form but missing the evidence that might have answered questions about how the enclosure was entered or used.