Somewhere in this part of County Cavan, a prehistoric monument that once stretched forty feet across the landscape has vanished entirely, leaving no visible trace. The ground gives no sign that anything was ever here.

What we know of it comes from the Ordnance Survey Memoirs, a remarkable series of parish-level descriptions compiled by military surveyors in the 1830s as part of a broader mapping project across Ireland. The memoir for Kildrumsherdan parish recorded a structure known locally as a Giant's Grave, a name commonly given in rural Ireland to elongated prehistoric mounds or stone settings that seemed too large to be the work of ordinary people. This one measured roughly 12.2 metres long and 3.65 metres wide, tapering at one end to just over a metre across. That narrowing, wedge-like plan is characteristic of a court tomb or a related megalithic form, the kind of communal burial monument built during the Neolithic period, several thousand years before the Christian era. Ruadhán de Valera and Seán Ó Nualláin, who catalogued megalithic monuments across Ireland during the mid-twentieth century, listed the site in their 1972 survey, though even by then certainty about its precise nature was limited. Whether the structure was dismantled for building material, absorbed gradually into field boundaries, or simply levelled during agricultural improvement in the intervening century and a half is not recorded.