To the untrained eye it looks like a slight irregularity in the field, roughly sixteen metres north to south and eight metres east to west, but beneath the turf lies a spread of burnt and fire-cracked stone that marks it as a fulacht fia, one of the most common and yet least understood monument types in the Irish countryside.

Fulachtaí fiadh (the singular is fulacht fia) are the remains of ancient cooking sites, typically Bronze Age in date, though some examples have been found to span other periods. The usual interpretation is that stones were heated in a fire and then dropped into a water-filled trough to bring the water to boiling point, after which meat could be cooked. The repeated heating and cooling eventually caused the stones to shatter and become useless, and the discarded fragments accumulated into the characteristic horseshoe-shaped or spread mounds that survive today. The site at Propoge is not an isolated example; it forms part of a cluster of three such monuments in the immediate area, suggesting that this particular slope was returned to repeatedly, or that a community here relied on the same general locale for this kind of communal activity. Small patches of burnt material noted to the east of the main spread hint that activity was not entirely confined to the central mound.