Cartographers working on the Ordnance Survey's six-inch maps in 1837 recorded it as a circular enclosure roughly thirty metres across, and the 1914 edition repeated that description without revision. On the ground, though, the shape is not quite a circle. The enclosure is better described as a D, its north-to-south extent running to about thirty-one metres while the east-to-west dimension comes to only fifteen, and the boundary that defines it is not a bank in the conventional sense but a scarp, a low step in the ground surface, rising from around twenty centimetres for most of its arc to about seventy centimetres along the eastern edge.

The enclosure sits on the east-facing slope of a drumlin, one of those elongated, rounded hills formed from glacial till that are scattered across the Irish midlands and north-west. The slope itself does some of the work that an earthen bank would otherwise do, allowing the scarp to taper away and merge with the natural gradient on the western and southern sides. A rath, a type of enclosed farmstead typically dating from the early medieval period and defined by one or more earthen banks and ditches, lies roughly a hundred and twenty metres to the west-south-west. Whether the two features are related in origin or simply neighbours by coincidence is not recorded, but their proximity on this quiet drumlin slope is suggestive of a landscape that was, at some point, more deliberately organised than it now appears.