It sits on the summit of Knocknaskea at 230 feet above sea level, sod-covered and roughly oval in plan, and its origins and date remain genuinely uncertain. That uncertainty is part of what makes it worth attention. A single angular quartz stone lies near the centre of its uneven top, positioned with just enough deliberateness to invite questions.

The mound measures roughly 6.8 metres east to west and 3 metres north to south, and rises only about half a metre at its highest, western end. The western half is better defined, with a slight raised internal rim and a broad sloping edge from which stones protrude; the eastern half has settled and slumped into the surrounding ground. At the eastern end of the mound's northern side, a large upright boulder, set deeply into the ground, stands alongside a smaller contiguous slab, the two together forming a kind of border between the mound and a low east-west field bank that runs across the hilltop. That field bank appears to cut into the northern edge of the mound, suggesting the mound came first, though by how much is unknown. The site appears on both the 1838 and 1921 Ordnance Survey six-inch maps, where the summit is recorded as a trigonometrical point, a surveying station used to fix precise geographical positions. A beacon stands about 20 metres to the south, added at some point to make the hilltop visible from the sea or from adjacent survey points.

Inishkea South was inhabited for centuries before its population left in the 1930s following a tragedy at sea, and the island retains various traces of early and medieval activity. Whether this mound belongs to that longer human story, or represents something older still, the landscape itself does not say.