The name, recorded in the Ordnance Survey Name Books as meaning 'the big man's grave', belonged to a wedge tomb, a form of megalithic burial monument common in the west and south of Ireland, typically dating to the late Neolithic or early Bronze Age, in which a long stone-lined gallery narrows slightly toward one end like a wedge in plan. By 1901, the Ordnance Survey map had already demoted it to a parenthetical: 'Tuamanirvore (Site of)'. The monument had been completely destroyed around 1895.

Before it vanished, the tomb was measured and described in enough detail to give a clear sense of what once stood in a cultivated field in the townland of Cappanahanagh, Parish of Abington, on the north-western edge of the Slieve Felim Mountains. According to the O.S. Name Book of 1840, it measured twenty-one feet long, four feet wide, and three feet high, with rows of large upright stones sunk deep into the ground along each side, and single stones of comparable size closing each end. The capstones had already been displaced by 1840, lying scattered to either side, with a heap of smaller stones nearby, overgrown with grass and moss. William Copeland Borlase recorded it again in 1897, noting its position on a small eminence near Lissguaire, and the Megalithic Survey of Ireland, compiled by Ruaidhrí de Valera and Seán Ó Nualláin and published in 1982, drew on these earlier accounts to confirm the site's classification as a wedge tomb, even in the absence of any surviving fabric.

There is nothing to see at Cappanahanagh today. The field where the tomb once stood gives no outward sign of what it held, and the site is of interest now primarily to those following the documentary record rather than the landscape. The value of stopping to consider it lies in what the Name Book descriptions preserve: a monument already partly ruined in 1840, its covering stones thrown aside, and yet still substantial enough to carry a name that invoked a figure of legend or memory. The 1840 map shows it; the 1901 map shows only its ghost. Whatever prompted its destruction in the intervening decades went unrecorded.