Carved into its face is an equal-armed cross, its ends fanning outward in a style known as splayed or expanded terminals. The stone is roughly a quarter of a metre across. It is also, in a precise sense, lost. Not removed, not destroyed, simply unlocated within the graveyard itself. Scholars have noted its existence since at least 1901, described it carefully, and yet nobody has been able to pin down exactly where among the graves it now sits.

The fragment was recorded by O'Reilly in 1901, who described it as appearing to be the corner of a rectangular leac, a flat grave-marker slab, suggesting it was already broken from a larger piece by that point. Crawford returned to it in 1913, adding his own measurements: ten inches wide, with a Greek cross five inches long incised into the surface. Subsequent researchers, including Ó hÉailidhe in 1959 and Healy in 1975, noted that its precise location within the graveyard had still not been established. The cross itself belongs to a type found at early medieval ecclesiastical sites across Ireland, where simple incised crosses were cut into stone as acts of devotion or to mark sacred ground. The Kill of the Grange complex is a particularly layered one, containing a pre-Norman church with a late medieval chancel, a holy well, a bullaun stone (a boulder with a worn basin-shaped hollow, often associated with early Christian ritual use), a graveslab, a stone font, and the base of a stone cross. Two further crosses from the old laneway into the graveyard have been removed entirely and are now held by the Office of Public Works in Trim, County Meath.

The graveyard lies on a low rise to the northeast of Kill Abbey Road, set in a green area that still carries some sense of remove despite the suburban development around it. Visiting with the 1901 photograph of the fragment in mind, a small triangular stone with a distinctive shaped top, is probably the most practical approach, though decades of searching by researchers have not produced a definitive identification. The surrounding complex repays careful attention; the bullaun stone, the font, and the church remains are all present and more readily examined. The missing cross-inscribed stone remains the quiet puzzle at the centre of the site.