The 1838 Ordnance Survey six-inch map marks a feature here with the label "Sweat Ho.", shorthand for a sweat house, and that cartographic notation is now the most tangible thing remaining of whatever once stood in this spot.

Sweat houses were small, low stone chambers, broadly comparable in function to a sauna, used in rural Ireland from at least the eighteenth century as a folk remedy for ailments including rheumatism and fever. A fire would be lit inside to heat the walls, the embers raked out, and the user would crawl in and sweat for a period before plunging into a nearby stream or lake. They are found across Ulster and Connacht in particular, and this site on Lough Bo was formally classified as one when it appeared in the Sites and Monuments Record in 1989. By 1995, however, it had been quietly dropped from the Record of Monuments and Places, and when the location was examined on the ground, no physical remains of any structure could be identified. The site is thought to date from after 1700, placing it within the period when sweat houses were most commonly in use across the Irish countryside.

What survives, then, is essentially a place-memory preserved by an early mapmaker. The 1838 survey caught something that later generations either lost track of or watched disappear, and the hillside above Lough Bo now carries only that faint cartographic echo of a once-practical piece of rural infrastructure.