The structure measures roughly 110 metres north to south and 55 metres east to west, its southern, western, and northern perimeters defined by a drystone wall two metres wide and up to two metres high. Drystone construction, which uses no mortar and instead relies on the careful selection and stacking of stone, is common across the west of Ireland, but walls of this mass and regularity suggest something more deliberate than a field boundary thrown up in an afternoon.

The eastern side of the enclosure is formed not by the main wall but by a townland boundary wall, and curiously, the enclosure leaves no trace at all beyond it to the east. Whether this represents an original design choice or the loss of an earlier element is unclear. Two entrances have been identified, one definite opening about four metres wide on the west side and a possible second on the south-west. Inside the enclosure, the remains of several houses are scattered across the interior, accompanied by large piles of field-clearance rubble, the kind of accumulated stone that accumulates over generations of farmers pulling rocks from ground they are trying to cultivate. An internal drystone wall further divides the north-east quadrant, suggesting the space was organised and reorganised over time. The site is considered possibly post-medieval in date, placing it broadly in the period after the sixteenth century, though no tighter dating has been established.

What makes Ballybaun worth attention is precisely this ambiguity. The enclosure is large enough to have functioned as a farmstead complex or a managed settlement of some kind, yet its relationship to the townland boundary and the absence of any eastern wall give it an unfinished or adapted quality, as though it was built to fit a landscape already divided in ways that no longer survive in any other form.