What road engineers encountered at Lisnagar Demesne in County Cork was the remnant of a fulacht fia, a type of prehistoric cooking or processing site found in enormous numbers across Ireland, typically consisting of a mound of burnt stone beside a water source and a trough in which liquid could be heated by dropping in fire-heated stones.

Excavation in 2003, carried out ahead of the construction of the N8 Rathcormac-Fermoy Bypass, uncovered the minimum footprint of the mound at roughly seven metres by six and a half metres. Beneath it lay an oval trough measuring approximately two metres by one point eight metres, along with three pits and thirty-three stake-holes. Some of those stake-holes may represent the post-settings of a structure associated with the site, though the evidence is not conclusive. What makes the location especially interesting is that a second fulacht fia sits roughly fifty metres to the north-north-east, on the opposite bank of a small stream. The presence of two such sites in such close proximity, separated by running water, raises quiet questions about how the area was used and by whom, and over what period.