The tallest is just 0.7 metres high, the lowest a mere 0.6 metres, which means anyone exploring them would need to crawl. They are connected by creepways, narrow passages designed to force entry into a crouch, and their ceilings are barrel-vaulted, meaning arched in a smooth curve rather than flat, a technique that distributes the weight of the earth above and prevents collapse. This is a souterrain, an underground stone or earth-cut structure associated with early medieval Ireland, typically built alongside a ringfort and used for storage, refuge, or both.

The structure was investigated in 1976 and documented by McCarthy in 1977. It is entirely earth-cut rather than stone-lined, which places it among the more modest examples of the type. The three chambers vary in size: the largest runs just over three metres in length and just over a metre wide, while the smallest is under two metres long. The original entrance appears to have been through what is now labelled chamber 3, suggesting the internal layout worked in reverse of how it might be approached today. Since the investigation, the site has been considerably disturbed, not by later construction or agricultural clearance, but by foxes, which have found the underground passages a congenial place to excavate and den. It is a quietly ironic fate for a structure probably built to shelter people from unwanted intrusion.