Not ruined, not buried under a later settlement, but simply lost, its precise location uncertain even now. What survives are the outlines: a motte and bailey at one end, a church site at the other, and somewhere in between, the ghost of a community that once numbered perhaps sixty households.

Old Ross was among the most significant manors held by the descendants of Strongbow, the Anglo-Norman lord whose invasion of Ireland in 1169 reshaped the country's political geography for centuries. When the Leinster estate was partitioned in 1247, Old Ross passed to Maud, wife of Hugh Bigod, Earl of Norfolk, and subsequently moved through the hands of various English landowning families. Accounts from the 1280s and 1290s suggest a settlement of real substance, and a description drawn up in 1305 lists two old halls, a chapel, a kitchen, a grange, and gardens. A motte and bailey is a form of early Norman fortification, typically an earthen mound topped with a wooden tower beside an enclosed courtyard, and the one here anchors one edge of where the settlement is thought to have lain. A stone castle was also present from at least the sixteenth century. By the 1680s, the traveller Robert Leigh recorded what he found: an old castle out of repair and fifty cabins. The arc from a manor with two halls and formal gardens to a ruinous castle and scattered cabins is, in its way, the arc of post-medieval Ireland in miniature.

The site repays quiet attention precisely because so little announces itself. The likely extent of the medieval settlement can be traced roughly between the earthwork remains of the motte and the old church site, across ground that gives almost no indication of what once stood there.