Yet this slight depression on a south-westerly slope near the Eslin River in the townland of Cavan, County Leitrim, is believed to be a sweathouse, an ancient form of dry heat therapy once common across Ireland. Sweathouses were small stone chambers, typically low-roofed and corbelled, in which a fire was lit, the embers raked out, and bathers crowded inside to sweat out ailments. They functioned, in effect, as an Irish sauna, and they appear in considerable numbers across Ulster and Connacht, though many have been lost, damaged, or simply forgotten.

This particular example has had a quietly eventful afterlife. When the current landowner's father arrived here in 1902, the structure was already a mystery to him. He took it for a lime-kiln, a reasonable enough assumption given that lime-kilns, stone-built furnaces used for burning limestone to produce agricultural lime, are a common feature of the Irish countryside. Deciding it was a safety hazard, he filled it in. It suffered a second indignity in the late 1950s, when harriers dug into it to flush out a fox. The structure's identification as a probable sweathouse rests partly on a reference in the Schools Manuscripts Collection, a vast archive of folklore gathered by Irish schoolchildren in the late 1930s. Volume 0215, Page 244 records a sweathouse in the townland of Cavan and describes it as a building of the finest type of its size, though the compiler did not note an exact location. The site was brought to wider attention in October 2021 by Aidan Harte, Project Co-ordinator of the Leitrim Sweathouse Project, an initiative dedicated to recording these overlooked structures across the county.

What survives today is a hollow measuring approximately 2.8 metres north to south and 2 metres east to west, with some earthfast stone visible on the downslope side, possibly the remains of original stone facing. It sits in pasture on a gentle ridge running north to south, about 75 metres east of the Eslin River. It is easy to walk past without a second glance, which is perhaps what has kept it intact at all.