No hollow in the ground, no protruding stonework, no surface trace of any kind betrays what was found here in the mid-1930s: a carefully constructed souterrain, a type of stone-lined underground passage or chamber commonly associated with Irish ringforts, likely used for storage, refuge, or both. What makes the discovery at Cush particularly interesting is not simply that the souterrain existed, but that it was not built entirely in stone. Part of it was timber, and that combination is what gives the site its quiet architectural distinctiveness.

The archaeologist Seán P. Ó Ríordáin excavated the northern quadrant of the ringfort at Cush between 1934 and 1935, publishing his findings in 1940. The ringfort itself is bivallate, meaning it was enclosed by two concentric earthen banks rather than one, a form that generally suggests higher status or more elaborate defensive concern. Within the interior of the northern quadrant, Ó Ríordáin uncovered a souterrain measuring approximately seven metres in length and just over a metre in width. The stone-built section was straight and parallel-sided, but attached to it was a timber-framed approach structure, the evidence for which survived only as four post-holes in the ground. Those post-holes showed that the timber entrance ran almost at right-angles to the main stone passage, and the ground on the southern side had been deliberately cut down to allow easier access. A second souterrain was later identified in the southern quadrant of the same ringfort, suggesting the site was more extensively modified underground than a surface glance would ever indicate.

There is, practically speaking, nothing to see at Cush today if you are looking for physical remains. Satellite imagery taken between 2011 and 2013 showed no visible surface traces of the souterrain, and more recent Google Earth images confirm the same. The site's value now lies almost entirely in the archive: Ó Ríordáin's published plans and field descriptions remain the primary record. For anyone with an interest in early medieval Irish settlement, the Cush excavations as a whole are worth seeking out in the literature, since the ringfort and its features were part of a broader campaign of fieldwork that produced detailed documentation of a type rarely available for sites of this kind.