The enclosure measures roughly 25 metres across, and while the dimensions are modest, the structure retains a legible outline that speaks to the care with which it was originally constructed.

This is a rath, the Irish term for a ringfort, the most common monument type surviving in the Irish countryside. Ringforts were typically built during the early medieval period, between roughly the fifth and twelfth centuries, and served as enclosed farmsteads for a single family or small community. They are defined by a raised earthen bank encircling a circular interior, and at Rockspring that bank still stands to an internal height of about 1.2 metres, with an external fosse, or ditch, dropping to a depth of around 1.45 metres. A counterscarp bank, a secondary low ridge thrown up on the outer edge of the ditch, runs from the north-north-west to the east-north-east, adding a further line of definition to the monument. The entrance faces roughly east-south-east and is wide enough at 4.2 metres to have admitted livestock as well as people. A short length of bank, about 6 metres long, sits just outside that entrance, spanning the silted-up fosse and likely marking some kind of outwork or access control. The fosse itself varies around the circuit: shallow to the south-east, silted up to the east-south-east, and waterlogged to the west, a reminder that drainage was as much a practical concern for early medieval farmers as it is for those working the land today.

The bank is heavily overgrown all the way around, and there is a narrow break of just over a metre to the north that may represent a secondary opening or a point of later disturbance. The overgrowth that makes the interior inaccessible also, in its own way, preserves it, keeping cultivation and casual disturbance at bay while the earthworks continue their slow subsidence into the surrounding slope.