What makes it quietly arresting is the layering of detail that survives: two concentric banks with a fosse, the ditch-like depression between them, enclosing a near-circular interior roughly 35.5 metres across. A rath of this kind, an earthen ringfort typically associated with early medieval settlement in Ireland, would once have been the fortified farmstead of a local family of some standing. The woodland has since grown up around it and over it, but the bones of the structure remain in fair condition.

The entrance causeway, six metres wide and positioned at the south-east, is unusually well defined for a site this overgrown, suggesting the original construction was substantial. Inside the north-east sector of the interior, a rectangular hollow roughly 8.7 metres long and aligned roughly north-north-east to south-south-west may indicate a souterrain, an underground stone-lined passage or chamber commonly built beneath ringforts for storage or refuge. If that identification is correct, it adds another dimension to the site: souterrains are often the most archaeologically productive features of a rath, preserving organic material and occasionally artefacts that surface earthworks do not. The name Doonwood itself appears to derive from this structure, "doon" being an anglicisation of the Irish "dún", meaning a fort or fortified place, which gives the surrounding townland its identity.