It measures roughly 22 metres north to south and 17 metres east to west, rising only about 0.3 metres above the surrounding ground. That modest rise is composed almost entirely of burnt stone and charcoal, the accumulated debris of repeated ancient cooking or heating activity. What makes the spot particularly striking is that a second, virtually identical mound lies just 15 metres to the east, as though whoever was using this place had simply moved along and started again.

These monuments are known as fulachtaí fia, singular fulacht fia, a term used to describe the remains of prehistoric cooking sites found in enormous numbers across Ireland. The typical method involved heating stones in a fire, then dropping them into a water-filled trough to bring it to a boil. The stones, cracked and rendered useless by repeated heating, were discarded into a mound beside the trough. Over centuries, the mound grew. The association with water is consistent here: the proximity of the stream 250 metres to the south would have provided a reliable source. The two mounds at Killeenleagh, sitting so close together, suggest sustained or repeated use of this particular spot, though whether they represent the same community at different times or something else entirely is not recorded.