The site is a fulacht fia, a type of monument found in considerable numbers across Ireland, typically consisting of a mound of fire-cracked stone and charcoal that accumulated beside a water source as people repeatedly heated stones in a fire and dropped them into a water-filled trough. The process boils water efficiently, and while cooking meat is the most widely accepted explanation, archaeologists have proposed other uses too, from textile preparation to bathing. What survives at Brough is a spread of this burnt material measuring roughly 22 metres on a north-east to south-west axis and 18 metres north-west to south-east, making it a reasonably substantial example.

The presence of a possible spring to the south-west is consistent with how these sites tend to be positioned. Access to a reliable water source was essential to whatever activity took place here, and fulachtaí fia are very often found close to streams, marshy ground, or springs. An archaeological monitoring report produced by Eachtra Archaeological Projects in June 2000 relates to this site, though it remains unpublished, meaning the fuller picture of what was observed during any groundworks at the time has not entered the wider record. The site itself was noted as being in tillage, which means the plough has almost certainly disturbed the upper layers of the mound over the years, gradually flattening and spreading material that might once have formed a more pronounced mound.