The rath here is a ringfort, the most common monument type in the Irish landscape, a roughly circular enclosure defined by an earthen bank and, in this case, an external fosse, which is simply a surrounding ditch. Farmers and their families built these enclosures during the early medieval period, roughly the fifth to twelfth centuries, as defended homestead sites. This one is a reasonably substantial example, with an internal diameter of approximately 26 metres and an overall diameter of around 40 metres when the bank and fosse are measured in.

The site was recorded on the first edition Ordnance Survey six-inch map of 1839 and confirmed again on the 1900 revision, meaning it had survived as a legible feature in the landscape for at least a century of modern mapping. Satellite imagery has since identified an entrance gap in the south-east quadrant of the enclosure, a detail not visible to earlier surveyors working at ground level. What gives the Killeen rath its particular interest, though, is its neighbourhood. A separate enclosure lies roughly 150 metres to the south-west, and two further ringforts sit approximately 270 metres and 440 metres to the east and east-south-east respectively. Finding four such monuments within half a kilometre of one another points to a stretch of land that was actively and repeatedly chosen for settlement, generation after generation, by communities who understood its value even when the wider world had moved on.