Man-made underground passage in Trostan

Located towards the bottom of the S-facing slope of a drumlin. A Man-made underground passage came to light in May 1963 and it was recorded by Ellen Prendergast of the National Museum of Ireland, but it could not be preserved. A subcircular chamber (int. dims 2.5m x 3m; H 2.5m) of rough corbelled walls had three drystone walled and lintelled passages radiating from it. At S an entrance (Wth 0.42-0.5m; H 0.55m) led to a passage (visible L 2m) and at NW an entrance (Wth 0.6m; H 0.65m) led to a passage (visible L 2m) but an entrance at N was completely blocked. Its precise location is not known now. (NMI, Topographical file) The above description is derived from the published 'Archaeological Inventory of County Monaghan' (Dublin: Stationery Office, 1986). In certain instances the entries have been revised and updated in the light of recent research. Date of revision: 28 July 2017