A souterrain is an underground stone-lined passage or chamber, typically built during the early medieval period and associated with nearby ringforts, most likely for storage or refuge. That this one has been infilled makes the description all the more compelling, a remembered interior preserved only in words.

The 1841 Ordnance Survey six-inch map already marked the spot as a "cave", placing it within the bounds of a ringfort on the same ground. By the time W. O'Connell wrote about it in 1938, the souterrain had been filled in, but its reputation had not faded. O'Connell recorded that it had been put to use during the Troubles, a period of revolutionary conflict in the early 1920s, when underground spaces of this kind offered cover that was both ancient and practical. The beehive-chamber description he preserved is framed carefully as something "often stated", passed along rather than personally verified, which gives it the character of a place known more through telling than through entry.