What makes this site at Blanchvillespark quietly arresting is what those features are thought to represent: a Bronze Age sweathouse, a small building in which heat and steam were deliberately generated, possibly for ritual cleansing or therapeutic purposes. The structure measures roughly four metres by two, oriented east to west, with what appears to have been an entrance at the eastern end and a small annexe attached there. Two pits sat inside, one of which, measuring about a metre long and less than half a metre deep, is interpreted as a trough, perhaps for holding water that was poured over heated stones to produce steam. A hearth was identified just outside, a couple of metres to the east.

The site was uncovered during excavations in 2007 and 2008, carried out in advance of road improvement works along the N9/N10 Kilcullen to Waterford route. Radiocarbon dating placed the structure firmly in the Middle Bronze Age, with a date range of approximately 1412 to 1269 cal BC. A separate pair of pits located about twelve metres to the south-west returned a closely matching date of 1426 to 1297 cal BC, suggesting coordinated activity across the area at roughly the same period. The structure itself was later sealed by a spread of burnt material, indicating it had gone out of use before the landscape above it shifted. Further along the same site, excavators found a burnt spread and a possible fulacht fia, a type of prehistoric cooking or hot-water site commonly identified by its characteristic mound of fire-cracked stones, located twenty-four and forty-two metres to the south-east respectively. The concentration of heat-related features within such a compact area points to a community for whom the controlled use of fire and hot water held considerable practical or ceremonial significance.