The cross is a tau cross, so named because its form resembles the Greek letter tau, a T-shape without the upper arm of the more familiar Latin cross. This particular example is roughly worked and carries no decoration, measuring 0.67 metres tall, 0.49 metres wide, and just 0.09 metres thick, a relatively slight and unassuming object that nonetheless represents a rare survival of an early Christian cross form.

The tau cross sits immediately to the north of a church site at Carrownaseer, within what is known as a cillín, a children's burial ground of the kind once found across rural Ireland, where unbaptised infants and others considered outside the bounds of formal Church burial were interred. It was recorded by Higgins in 1987 and appears to have been brought to this spot and reused as a grave-marker, repurposed from whatever earlier context it belonged to. A cross-slab at the same site has been similarly reused, suggesting that this small burial ground became something of a repository for older carved stonework whose original function had long since been forgotten. The exact origins of the tau cross, and what it once marked or adorned, remain unknown.