The island is a crannog, a type of man-made or partially man-made lake dwelling constructed from timber, peat, brush, and stone, commonly used in Ireland from the Bronze Age through to the early medieval period and occasionally beyond. That a building survives on this one, however ruinous, gives the site a quiet particularity worth pausing over.

The structure is modest by any measure. Roughly square in plan, it runs about 3.8 metres north to south and 3.1 metres east to west, with surviving walls standing only around 0.8 metres high and between half a metre and 0.6 metres thick. It is built in drystone technique, meaning no mortar was used, the walls held together instead by the careful arrangement of flagstones. As recorded by Crumlish in 1996, the building has clearly seen some interference over the years. The northern wall and part of the western wall have been partly demolished and rebuilt, as have the upper courses of the eastern wall, and rubble from the structure lies scattered to the west and northwest of it. Whether these interventions were attempts at repair, episodes of deliberate dismantling, or something else entirely, the notes do not say. What remains is a small, battered shell on an island that was itself a feat of construction, sitting in a lough in the Burren's quiet interior.