To the casual eye it is easy to dismiss, but the dark, fire-cracked stone packed into its interior marks it out as a fulacht fia, one of the most widespread and quietly puzzling monument types in the Irish archaeological record. What is particularly notable here is that a second, near-identical example lies roughly a hundred metres to the north, the two sites forming an uncommon pairing in the same stretch of ground.

A fulacht fia, sometimes called a burnt mound, is broadly understood to have functioned as a prehistoric cooking site, though some researchers have proposed additional uses including dyeing, bathing, or brewing. The typical arrangement involves a timber-lined trough dug into the ground near a water source, into which heated stones were dropped to boil water. The stones, once cracked and spent, were raked out and discarded, accumulating over repeated use into the horseshoe-shaped or oval mounds that survive today. The site at Lislehane follows this pattern closely: the oval mound, measuring fifteen metres north to south and eleven metres east to west, retains the characteristic central hollow where the trough would once have sat. Its position immediately beside marshy ground is equally typical, since ready access to water was essential to the whole process. Fulachta fia are generally dated to the Bronze Age, roughly 2000 to 500 BC, though some examples fall outside this range.