What remains is a disturbed spread of fire-cracked stone and charcoal-darkened earth, with some of that material redeposited on the opposite bank of a recently dug drain. It is a modest, unremarkable sight on the surface, but the material underfoot is the remnant of a fulacht fia, one of Ireland's most numerous yet least understood prehistoric monument types. A fulacht fia is essentially a cooking site, typically Bronze Age in date, where water held in a timber or stone trough was heated by dropping fire-heated stones into it. The shattered, blackened stones, cracked by repeated thermal shock, then built up over time into the low horseshoe-shaped mounds that survive in their thousands across the Irish landscape.

This particular site was probably one of a pair. Bowman, writing in 1934, recorded two fulachta fiadh on land belonging to a C. Daly in this area, and the Rathranna example is likely one of those two. The second, recorded separately, appears to have stood nearby. By the time the site entered the archaeological record more formally, the intervention of a drainage scheme had already done considerable damage, scattering burnt material to both sides of the new cut. Such disturbance is not unusual for monuments of this type. Fulachta fiadh tend to occupy low-lying, marshy ground close to water sources, which makes them attractive targets for land drainage over the centuries, and means that even a relatively modest piece of agricultural engineering can displace material that has lain undisturbed for three millennia.