In 1990, a rough circle or arc of boulders was being cleared from the south-eastern slope of Kill hill in Kildare when workers uncovered something that had been sitting quietly beneath it, or perhaps within it, for several thousand years: a single boulder of green Silurian slate, measuring roughly 1.54 metres long and just under a metre wide, with two decorated surfaces covered in prehistoric rock art.

The carvings belong to a tradition known as cup-and-ring art, a form of prehistoric mark-making found across Atlantic Europe, in which shallow circular depressions, known as cupmarks, are surrounded by concentric pecked rings. On this boulder, the decoration is unusually complex. Two large central motifs dominate the surfaces, each consisting of cupmarks enclosed by alternating bands of small pecked cups and rings. Elsewhere on the stone there are ringed cups enclosed by further bands of small cups, simple ringed cupmarks, at least one of which has radial grooves running outward from the centre, and a broad spread of small shallow cupmarks covering much of one face. The circle of boulders that had surrounded it, made largely of the same Silurian slate with some red conglomerate mixed in, may have been the remnants of a prehistoric cairn, a stone mound typically raised over a burial or used to mark a significant place. That identification was suggested by Anna Brindley, who examined the site between 1987 and 1991. The decorated stone itself was transferred to the National Museum of Ireland in 1993.

The boulder is now held at the National Museum of Ireland, whose main archaeology collection is displayed at Kildare Street in Dublin city centre. The museum's prehistoric holdings are extensive, and individual objects do not always remain on permanent public display, so it is worth checking with the museum directly before visiting with this stone specifically in mind. The original find site on Kill hill in Kildare carries the record reference KD020-018 in the national Sites and Monuments Record, and while the decorated boulder is long gone from the slope, the landscape itself remains, a quiet hill that briefly yielded something very old when someone decided to clear away the stones.