Beneath a covering of grass and roughly sixty centimetres of accumulated peat, there is a carefully constructed ring-cairn, a type of Bronze Age monument consisting of a central mound of stones encircled by a deliberately built outer ring, with a flattened berm, a narrow level shelf of ground, separating the two elements. The whole structure stretches just over twenty metres across at its widest point, yet its profile is low and the peat has softened its outline considerably, giving it the appearance of a gentle rise rather than anything made by human hands.

The dimensions recorded for the site are precise enough to suggest a monument that was once well-defined. The central mound, subcircular in plan, measures roughly fifteen and a half metres east to west and just over thirteen metres north to south, with a flat top around ten metres wide. The outer stone ring, which still stands to an external height of between half a metre and seventy centimetres in places, wraps around the cairn at a width of up to nearly three metres. Ring-cairns of this kind are generally associated with funerary or ceremonial activity during the Bronze Age, though without excavation it is rarely possible to say more about the people who built a particular example or what rites they may have performed there. What is clear at Kilroosk is that the eastern and south-western edges of both the central cairn and the outer ring have suffered some damage, while the peat growth across the top has continued to obscure the stonework beneath.