The structure is rectangular, roughly eleven and a half metres from north to south and four and a half metres wide, with what appears to have been an open or entrance side facing south. What holds it together, barely but distinctly, is an L-shaped earthen bank running along the north and east sides, rising less than half a metre above the exterior ground level. To the west, the building borrows its boundary from the scarp edge of a larger adjoining enclosure, nearly thirty metres long and eighteen metres wide, whose low earthen lip does some of the structural work that a wall might otherwise have done.

The building sits roughly mid-way along the eastern edge of the Railstown medieval settlement, a broader complex of earthworks in undulating south Tipperary terrain. Medieval rural settlements of this kind, sometimes called deserted medieval villages or townland-scale agricultural clusters, were once far more numerous across Ireland than the landscape now suggests. Most were abandoned during or after the upheavals of the fourteenth and fifteenth centuries, leaving behind only the faintest compression of ridge and furrow, enclosure banks, and building platforms. At Kilbragh, this particular structure is one component within that larger settlement pattern, its modest dimensions consistent with a domestic or agricultural function, though the record does not specify which. The open southern aspect is a common feature of medieval Irish buildings, offering both light and access while the bank to the north and east provided shelter from prevailing wind.