The enclosing stone walls, high and largely unremarkable at first glance, give themselves away at the base: the lower courses are noticeably thicker than those above, suggesting the present wall was built up on foundations that belong to an earlier structure entirely. The yard measures roughly 38 metres north to south and 20 metres east to west, bounded on the south by a diagonal concrete wall and a derelict nineteenth-century house. Apart from those stubborn lower courses, nothing visible in the yard appears to predate the late eighteenth century.

The name attached to the site, Barrymore Barn, points toward its probable origins. Castlelyons Castle, about 300 metres to the northwest, was the former seat of the Earls of Barrymore, and the barn and an adjacent stables were most likely part of the castle's working estate. The 1842 Ordnance Survey six-inch map places the barn close to those stables, suggesting the two buildings stood together as a functional unit. Later editions of the same map shift the label eastward, to a position now occupied by a late nineteenth-century Parochial House, which may simply reflect cartographic drift or changes on the ground as the estate declined and other buildings replaced it. The barn's name survived the physical structure, floating across the map as the landscape around it was steadily repurposed.