What makes the Knockmanagh standing stone more interesting is the company it once kept, or may have kept. It was absent from the Ordnance Survey's meticulous six-inch mapping of 1842, which is itself a small puzzle, since that survey was generally thorough in recording upright stones across the Irish landscape.

When the antiquarian Bowman catalogued the area in 1934, he noted four standing stones on land then belonging to a R. Sheehan, and the Knockmanagh stone is likely one of that group. Standing stones, which are exactly what they sound like, single or grouped upright stones erected during prehistory, most commonly during the Bronze Age, are scattered across Cork in considerable numbers, though their precise purposes remain debated. Bowman's description of stone (d) in the group, measured in the older imperial reckoning as roughly three feet nine inches tall with a girth of nearly twelve feet, corresponds reasonably well with the dimensions recorded here: one metre high and about one and a half metres by three-quarters of a metre in cross-section. The stone is rectangular in plan but irregular in shape, which is typical of the unworked local material used for such monuments. Its position gives a commanding view in all directions, a quality shared by many standing stones and one that has fuelled persistent speculation about their roles in marking territory, astronomy, or seasonal ritual.