It is easy to walk past without knowing it is there at all, and even those who do find it may not immediately grasp what they are looking at.

This is a souterrain, a type of underground passage constructed using drystone walling, meaning stones laid without mortar, relying entirely on their own weight and careful placement to hold the structure together. Souterrains are found across Ireland in association with early medieval settlement sites, and were likely used for storage, refuge, or both. This particular example sits within a rath, which is a circular earthen enclosure that typically surrounded a farmstead during the early medieval period, roughly the fifth to twelfth centuries. The souterrain itself runs more than 6.8 metres in length and curves slightly from east to west. At its widest it reaches 1.5 metres, and at its highest point just 0.68 metres, making any exploration a strictly horizontal affair. The structure is poorly preserved, and the two openings that currently allow access are not the original entrances, meaning the passage has been disturbed at some point since it was built and has lost whatever arrangement once controlled entry to it.