It measures roughly 21 metres north to south and 12 metres east to west, rising only about 40 centimetres from the surrounding pasture. That modest profile, however, marks it as a fulacht fia, a type of Bronze Age cooking site found in great numbers across Ireland. The characteristic ingredient is burnt stone: rocks were heated in fire and then dropped into a water-filled trough to bring the water to a boil, a process repeated until the stones cracked and shattered. Over time, the discarded fragments accumulated into the low, horseshoe-shaped or linear mounds that survive today, still dark with fire-stained material.

At Shanaknock, the burnt material does not stop at the mound's edge. A spread extends a further 8 metres outward from the eastern side, suggesting repeated, sustained use of the site. This is likely one of three fulachta fiadh noted in the area by Bowman in 1934, recorded in association with land then belonging to a D. O'Riordan. The clustering of three such monuments in one locality is not unusual; fulachta fiadh are often found in groups, sometimes along watercourses, which would have supplied the water essential to their function. The proximity to a drain here fits that broader pattern well.