What makes the earthwork at Ardogelly quietly anomalous is its shape: not round, but triangular, a geometry almost never associated with early Irish enclosures and one that immediately raises the question of whether this was a deliberate choice or an accident of topography and time.

The enclosure sits on a low rise in open pasture and covers a raised area of roughly 50 metres on its longer axis. Two sides of the triangle, the south-east and the south-west, are defined by a substantial earthen bank, a type of raised boundary construction used throughout early medieval Ireland to demarcate settlements, farmsteads, and places of local significance. The bank on the south-east side is around seven metres wide, and the accompanying fosse, or external ditch, runs five to six metres across and drops more than a metre in depth where it is best preserved. At the eastern lip of this fosse there are traces of what may be a second, outer bank, suggesting the enclosure was once more elaborately defended or delineated than it now appears. A gap of about two and a half metres in the south-east bank, with a causeway crossing the fosse beside it, marks what is understood to be the original entrance. The northern side of the triangle tells a different story: it has been largely levelled, its outline now barely readable in the ground. A field boundary running roughly east-north-east to west-south-west cuts across the northern half of the interior, a later imposition that has further obscured whatever the enclosure once contained. By the time the Ordnance Survey recorded the area in 1913, the site was already being read simply as a triangular field, its ancient character folded into the ordinary geometry of the working landscape.