The enclosure sits on top of a low drumlin, one of those smooth, elongated hills shaped by glacial drift that give this part of Ireland its rolling, hummocky character. Its interior measures just over 38 metres east to west and nearly 35 metres north to south, bounded by an earthen bank and an outer fosse, the term for a defensive ditch, that still reads clearly in the landscape despite centuries of grass and rush growth softening every edge.

The bank itself is modest internally, rising only ten to twenty-five centimetres above the enclosed ground, but from the outside it presents a face of nearly two metres, giving the structure considerably more presence when approached from below than from within. The fosse at its base is about two and a half metres wide. Earthen enclosures of this kind are broadly classed as ringforts in Irish archaeology, a monument type built and used across many centuries, most commonly associated with the early medieval period, roughly the fifth to the twelfth centuries, and typically serving as enclosed farmsteads for a single family or small community. What makes Carrickbaun quietly arresting is the absence of any surviving entrance gap, a feature that usually survives in some form even in heavily degraded examples. Whether the original causeway across the fosse was simply filled in over time or was never substantial enough to leave a trace is not recorded. Around 2010, commercial forestry was planted across the surrounding land, but the fort itself was left clear, an island of older ground use inside a more recent one.