The stone is conical in shape, roughly 34 centimetres tall and tapering from a base diameter of 36 centimetres down to 19 centimetres at the top, where a rectangular socket, cut slightly off-centre, would once have held the shaft of a cross above it. The top of the block is broken, so the socket itself is incomplete, and the shaft it supported is long gone.

The stone was first recorded by the scholar R.A.S. Macalister between 1916 and 1917, when it was still in place against the nave wall of St. Caimin's church, one of several early Christian structures on the island. Inis Cealtra, sometimes called Holy Island, is a monastic site of considerable age, associated with saints and pilgrimage traditions reaching back to the early medieval period. At some point after Macalister documented it, the cross base was moved to the OPW chalet on the island for safekeeping, separating it from its original architectural context. What Macalister saw as a feature of the church fabric is now an object in storage, its original position only recoverable through his published note.