No surface trace remains visible today, which means the structure exists in a curious state, known about through local information but effectively invisible, a piece of underground architecture that has quietly withdrawn from the landscape.

The passage is a souterrain, a type of underground chamber or tunnel constructed during the early medieval period in Ireland, typically built from dry stone and used in association with ringforts as storage spaces, places of refuge, or both. The ringfort here, known as a rath, is an enclosed settlement site of the kind built by farming families across Ireland roughly between the fifth and twelfth centuries, consisting of a roughly circular area defined by earthen banks. The souterrain at Ballinlough sits within the interior of such a rath, and local knowledge records that its entrance gave onto a stone-built passage, reached by lifting or shifting a covering flagstone. That entrance is no longer apparent at ground level, leaving the passage effectively buried under its own concealment.