Most ringforts, the circular earthwork enclosures built by farming families across Ireland roughly between the fifth and twelfth centuries, are fairly straightforward in plan. This one at Ballinteskin is D-shaped, a deviation that hints at some combination of topography, intention, or later disturbance that has yet to be fully untangled.

The enclosure measures approximately 61 metres east to west and 61 metres north to south, defined by a fosse, which is a ditch dug to demarcate and defend the interior, around three metres wide though now quite shallow at roughly fifteen centimetres deep. Along the northern and eastern edges, a modern field bank has been laid directly against the outer rim of that fosse, the kind of practical agricultural reuse that slowly erodes the legibility of ancient earthworks over generations. What makes Ballinteskin particularly interesting is what the Ordnance Survey's six-inch map of 1838 recorded: a distinct inner circular element, about forty metres in diameter, sitting within the larger enclosure. That detail raises the possibility that this was originally a bivallate ringfort, meaning one with two concentric enclosing elements rather than one. Bivallate examples tend to be associated with higher-status occupants in early medieval Ireland, the extra ring of earthwork suggesting additional effort, additional prestige, or simply additional security. Whether the inner element survives visibly today is less certain; the 1838 surveyors caught it at a moment when it was apparently still distinguishable.

The site rewards patient looking rather than dramatic discovery. The fosse is subtle now, and the D-shape only really becomes apparent when you consider the full perimeter rather than any single section of it.