At 651 feet above sea level, the summit of Lyons Hill in County Kildare carries a concrete Ordnance Survey triangulation pillar, which is probably not what most people would expect to find at a one-time seat of Leinster kings. The pillar sits on a low cairn, roughly ten metres across and a metre and a half high, and the whole ensemble sits within the faint remains of an oval enclosure whose outer ditch and scarp-edged banks have been softened almost to nothing by centuries of grazing. Thin, flaggy facing-stones survive in a short arc on the western side and appear intermittently to the north-west where the sod has worn away, but for the most part the monument asks a good deal of the imagination.

Killanin and Duignan, writing in 1967, placed Lyons Hill among the early royal seats and public assembly places of the kingdom of Leinster, and identified it later as the chief seat of the Mac Giolla Mo-Cholmógs, a branch of the Uí Dúnlainge dynasty that dominated Leinster politics through the early medieval period. Inauguration sites of this kind typically combined a ceremonial enclosure with a prominent cairn; the elevated position, commanding panoramic views to the south, west, and north-east, would have made the hill visible from a considerable distance and lent any public assembly held there a suitably theatrical quality. The same authors noted that Lyons Hill is among the sites claimed as the location of Daniel O'Connell's duel with John D'Esterre in 1815, a contest that ended with D'Esterre fatally wounded and O'Connell reportedly haunted by the episode for the rest of his life. Whether the hill has any genuine claim over rival locations is unresolved, but the association adds a peculiar historical layering to a place already carrying several centuries of political significance.

The monument sits in former demesne land, and the enclosure's outer fosse, broad and shallow at roughly twelve metres wide and less than a metre deep, runs along the eastern side where it separates the oval from a natural spur of the hill. The scarp itself stands no more than about ninety centimetres high in its best-preserved sections. Visitors prepared to look carefully at ground level, particularly after grazing has exposed the stonework, will find more to see than the casual eye suggests.