It is a fulacht fia, a type of prehistoric cooking site found in enormous numbers across Ireland, and one of the more intriguing recurring features of the Irish Bronze Age landscape. The mound here measures roughly 8.8 metres north to south and just over 8 metres northwest to southeast, rising to about 0.8 metres at its highest point, with a four-metre opening facing northwest.

Fulachtaí fia, the plural form, are typically interpreted as outdoor cooking places, though debate continues about whether they served other purposes, perhaps for bathing, brewing, or textile processing. The basic principle is consistent across thousands of known examples: stones were heated in a fire, then dropped into a water-filled trough to bring it to the boil. Over repeated use, the stones shattered from thermal shock and were discarded in a crescent-shaped heap around the trough, which is exactly the kind of accumulation visible at Blueford. The horseshoe or crescent plan, with an opening on one side, is the classic signature of the type, and the northwest-facing gap at this site fits that familiar pattern. Most fulachtaí fia date to the Bronze Age, broadly between 1500 and 500 BC, though some earlier and later examples are known. They tend to cluster near water sources, since a reliable supply was essential to the whole process.