It does not appear on Ordnance Survey mapping, and it was only formally reported in October 2021 by Aidan Harte, Project Co-ordinator of the Leitrim Sweathouse Project, an effort to locate and document these frequently overlooked monuments before they disappear entirely. A sweathouse is essentially an early Irish version of a sauna: a low, airtight chamber into which hot stones were placed, generating intense heat for therapeutic or medicinal purposes. They are found in some concentration across Ulster and Connacht, and Leitrim has an unusually high density of them, though many remain unrecorded.

The Cornageeha example is built entirely without mortar, a technique known as drystone construction, and takes a D-shaped plan internally. It is compact but not cramped by the standards of the type: just under two metres long inside, around one and a half metres wide, and tall enough internally to sit upright at just over 1.6 metres. Entry is through a small, slightly funnel-shaped opening on the north-west face, barely half a metre wide and just over half a metre tall on the outside, which would have helped retain heat once a person crawled inside and the entrance was blocked. What makes this particular structure worth close attention is its roof. Rather than a simple corbelled or slab-laid ceiling, it uses an A-shaped system: a single central stone lintel spans the width of the chamber like a beam, resting on a pillar at the west end, and from this ridge-piece, inclined lintels slope down on either side to form a pitched roof. It is a small but genuinely clever piece of engineering in undressed stone.

Another sweathouse stands approximately 560 metres to the east, suggesting that this corner of Cornageeha once saw regular use of these structures, perhaps by a farming community for whom access to any other form of medical treatment was limited. The site is currently in good condition, though a young tree has begun pushing against the roof, a slow but real threat to the very lintel arrangement that makes it distinctive.