A souterrain is an underground stone-lined passage or chamber, typically constructed during the early medieval period in Ireland, most often associated with ringfort settlements. They were built for a variety of purposes, storage of perishables being the most practical explanation, though some may have served as places of refuge or concealment. Their presence in a landscape is easy to miss entirely, the ground above giving little away.

Corrabaun is a small rural townland in Mayo, and beyond the fact of the souterrain's existence and classification as a recorded monument, the specific details of this particular structure remain publicly sparse. What is known is that it has been identified and catalogued, placing it within a broader pattern of early medieval activity across the west of Ireland, where souterrains are found in considerable numbers, often clustered around areas of historic settlement. Mayo has a notable density of such features, many of them still incompletely studied or described in accessible form.