This is a sweathouse, an tigh alluis in Irish, a type of structure once used across rural Ireland as a form of folk medicine. The principle was straightforward: a fire was lit inside the stone chamber for several hours, the ashes raked out, and a person suffering from rheumatism or similar ailments would crawl inside and sweat out whatever ailed them before plunging into a nearby stream or pool. The Cloonfinnan example survives as a sub-circular, roofless structure, its original corbelled roof long since fallen or removed, but the chamber itself intact enough to read clearly on the ground.

The structure appears, unnamed, on the Ordnance Survey twenty-five-inch map of 1906, which is already a hint that by then it had slipped from active use into something merely noted. Local memory, preserved in the Schools Manuscript Collection compiled by pupils at Annaduff National School during the 1930s folklore survey, mentions it four times. Those accounts identify the late Patrick Faughnan as the man who operated it, and note that by the time the children were collecting stories, the structure was already in disrepair. That the sweathouse features in folklore gathered at Annaduff N.S. and attributed to a contributor named Pat Reynolds of Culmore, Dromod, suggests it was remembered as a working place within living memory, not simply as a ruin. What makes the site stranger still is what stands roughly twenty-five metres to the south-southwest: a portal tomb, a megalithic monument thousands of years older than any sweathouse tradition. The proximity is almost certainly coincidental, but the layering of two entirely different kinds of human need and practice on the same low hillside gives the place an odd density.

The site was reported in October 2021 by Aidan Harte, Project Co-ordinator of the Leitrim Sweathouse Project, an initiative working to document these overlooked structures across the county before the remaining examples deteriorate further. The woodland setting means the chamber can be difficult to spot, and the roofless state means there is less to see than the original structure would have offered, but the sub-circular walls and north-facing entrance are legible to anyone who takes the time to look.