The structure is a rath, the earthen variety of ringfort, a form of enclosed settlement that was built in enormous numbers across Ireland roughly between the early medieval period and the Norman arrival. Thousands survive in various states of preservation, yet each one carries its own particular shape and set of details that repay a closer look.

This example at Tullyneasky is roughly circular and measures about thirty metres in diameter, enclosed by an earthen bank rising to around one and a half metres. Beyond that bank, to the east and northwest, lies an external fosse, a defensive ditch, cut to roughly half a metre in depth. To the northwest there is also a possible counterscarp bank, an additional low ridge thrown up on the outer edge of the ditch, which would have made the whole perimeter more formidable to anyone approaching from that direction. A gap of five metres in the bank to the southwest most likely marks the original entrance, the point where whoever lived here came and went. The asymmetry of the surviving earthworks, with the fosse and possible counterscarp concentrated on the eastern and northwestern sides, hints at where the occupants felt most exposed or where the topography made defence most necessary.