It left no mark on the surface, no mound, no hollow, no trace at all to suggest that anything lay underneath. It came to light through tillage, the kind of accidental discovery that quietly rewrites the archaeology of ordinary farmland.

A souterrain is an underground stone-built structure, typically associated with early medieval settlement in Ireland, and thought to have served as a place of refuge, storage, or both. The one at Lisheens is a modest but carefully constructed example. When McCarthy recorded it in 1977, he found a single sub-rectangular chamber just over three metres long, roughly one and a half metres wide, and little more than a metre high; roofed with flat lintels laid across the stone walls. The long axis runs north to south. At the southern end there was a creepway, a low connecting passage designed so that a person would have to crawl through it, framed by two jamb stones and capped with its own lintels. It was blocked at the time of recording. The northern end had partially collapsed. The chamber is small enough that even in good repair it would have been a cramped space, which is part of what makes souterrains so quietly unsettling; they were built to be used by people, and used in circumstances where concealment mattered.