The structure is a souterrain, an underground stone-lined tunnel or chamber typically built during the early medieval period, most often associated with ringforts and used for cold storage, refuge, or concealment. What makes this particular example notable is precisely what is no longer there: the way in has been sealed, and the interior is inaccessible, yet the outline of that sealed entrance remains visible to anyone who knows to look for it.

By the time P. J. Hartnett recorded the site in 1939, he noted simply that it was "now closed", suggesting the infilling had already taken place well before the mid twentieth century. Hartnett's observation, published in 1939, is the only dated account of the souterrain's condition on record. The ringfort it belongs to, a type of enclosed farmstead that was the dominant form of rural settlement in early medieval Ireland, still survives at the site, and the souterrain occupies its northwest quadrant.