No upright remains, no fallen slabs visible above the grass; the site exists almost entirely in the documentary record, kept alive by a pencil sketch made during the 1842 Ordnance Survey fieldwork in County Kerry. That sketch, later reproduced by the archaeologist Seán Ó Nualláin in 1984, shows eleven low standing stones, known in Irish archaeological parlance as gallauns, arranged in a rough circle perhaps ten metres across, with a single stone at its centre. The surveyor's caption is matter-of-fact about their condition even then: the stones varied from two to three feet in height, and some were already lying flat.

What makes the Killowen circle particularly intriguing is the detail recorded about that central stone. It appears to have carried a cupmark on its upper surface, one of those deliberately ground, shallow depressions found on prehistoric stones across Ireland and Britain, whose precise purpose remains unresolved. Ó Nualláin, writing in 1975, went further, suggesting the central stone may not have been a simple standing stone at all but rather a capstone belonging to a boulder-burial, a type of megalithic monument in which a large flat stone is propped over a small boulder setting, typically interpreted as a grave. If he is right, the circle at Killowen was arranged around a burial monument, a pattern with parallels elsewhere in Kerry's prehistoric landscape. By 1846, when the Ordnance Survey published its six-inch map, the circle was recorded but already in poor condition. At some point after that it disappeared from the ground altogether, leaving only the earlier sketch as evidence of what had been there.