This is a souterrain, a type of structure built during the early medieval period in Ireland, typically consisting of stone- or earth-cut passages and chambers used for storage, refuge, or both. What makes the Teerelton example quietly striking is its scale: four separate chambers, connected by the narrow passages known as creepways, through which a person would have had to crawl to move from one space to the next.

The souterrain came to wider attention around 1965, when it was discovered, though the knowledge of its layout comes from local information rather than formal excavation. The four earth-cut chambers suggest a substantial construction effort, and the presence of a possible ringfort approximately fifty metres to the north-west adds meaningful context. Ringforts, the enclosed farmsteads that dot the Irish countryside from the early medieval period, were frequently associated with souterrains, which were often built into or beside their banks. Whether this souterrain served the occupants of that enclosure is unconfirmed, but the proximity is unlikely to be coincidental.