There is nothing to see at the surface. The entrance was blocked up at some point in the past, and no visible trace of it remains today.

A souterrain is an underground passage or chamber, typically built from dry-stone walling, and associated in Ireland with early medieval ringforts and cashels. Cashels are the stone-walled variant of the ringfort, a class of enclosed settlement that served as a farmstead or residence during the early medieval period. Souterrains were used for storage, refuge, or both, and are found across the country in varying states of preservation. The one recorded at Barroe sits within an already-identified ringfort, and its existence rests entirely on local oral tradition rather than excavation or survey. The dry-stone construction attributed to it would be consistent with what is known elsewhere, but whether anything structurally intact survives underground is unknown.

What makes this site quietly interesting is precisely its absence. The blocked entrance and the lack of any surface evidence mean the souterrain exists, for now, only as a piece of local memory attached to a field in Mayo. That memory was considered worth recording, which is itself a small reminder of how much of the Irish early medieval landscape persists in this form, known but unseen, held in place by the people who live nearest to it.