It is a rath, the Irish term for a roughly circular enclosure defined by an earthen bank and ditch, built during the early medieval period as a farmstead or place of habitation. What makes the Killeline example quietly odd is precisely this context: a structure that once anchored a family's landholding and daily life now sits within a leisure landscape that has, in practical terms, preserved it almost by accident.

The enclosure is nearly circular, measuring 25.8 metres north to south and 27 metres east to west, which puts it in the modest but typical range for this type of monument. Its defining feature is a scarped edge, meaning the ground has been cut or shaped to create a slight but deliberate drop, rather than a raised bank piled up from dug material. That edge survives to a height of around half a metre and extends to a width of roughly six metres. It is most clearly readable on the arc running from the north-west around to the east, and becomes almost imperceptible on the opposite side. The interior slopes gently downward toward the north, and the whole area is under grass. Denis Power, who compiled the record uploaded in August 2011, noted that a field drain runs along the eastern side about eight metres out, and that a field boundary which once lay just south of the enclosure has since been removed.

Visitors to Killeline who know what to look for can find the rath within the golf course grounds, though access will depend on the facility's arrangements at any given time. The monument is best understood from ground level by walking the perimeter and watching for the change in gradient that marks the scarped edge, particularly on the north-western to eastern arc where it is most legible. The grassed interior offers little visual drama, but standing inside and looking north along the gentle slope gives some sense of the original siting choice, a position that is slightly elevated without being exposed. The removal of the southern field boundary, a common casualty of agricultural and development pressure, means the immediate historic landscape around the rath is only partially intact, though the enclosure itself has survived in reasonable condition.