At Doire Mhór Thiar, dense vegetation now fills much of the interior and creeps over portions of the enclosing bank, so that the structure reads less as a clearly defined monument than as a slightly raised, overgrown anomaly in the landscape. What gives it away is the bank itself, which climbs to a maximum of 1.6 metres above the surrounding field, and the faint external fosse, a shallow ditch roughly 2 metres wide, that traces an almost complete circuit around the outside. The entrance, if it survives at all, is thought to lie somewhere in the southern sector, where the bank drops to barely 0.4 metres and becomes almost imperceptible from inside.

The fort is univallate, meaning it has a single enclosing bank rather than the multiple concentric rings found at more elaborate sites, and its internal diameter measures 23.5 metres, a fairly typical size for this class of monument. These earthwork enclosures are associated broadly with the early medieval period in Ireland, roughly the fifth to twelfth centuries, and are thought to have served primarily as farmsteads or settlement enclosures for farming families of modest means. The bank here is a composite construction: the inner face is largely earthen, while the outer face is made up mainly of small stones, some of which, particularly along the western and north-western edges, are likely to be field clearance material gathered over centuries rather than original fabric. A short run of stones along the inner base at the west-south-west may represent the remnant of a revetment, a facing used to stabilise the bank's inner edge, though only about 2 metres of it remain visible, protruding just a few centimetres above the surface. The site sits about 500 metres south of Tralee Bay, at the northern foot of the Slieve Mish mountains, a position that places it at the edge of a well-settled and well-surveyed stretch of the Dingle Peninsula, documented in J. Cuppage's 1986 archaeological survey of Corca Dhuibhne.