O'Brien's Castle

In SE corner of Dún Formna (GA120-017001-). Known locally as Caisleán Uí Bhriain, it consists of a two-storey rectangular keep (L 13.2m, Wth 7.6m), in fair condition, and now a Nat. Mon. Present access is via a late ope in NE wall. Above this, on 1st floor, is the original doorway, flanked by two beam-holes for external wooden stairs. This doorway gave access to a hall occupying the whole of 1st floor, the vaulted floor of which has largely collapsed. Access to the ground floor basement, of three vaulted chambers, appears to have been via an opening in the roof of the central chamber. Intramural stairs in thickness of SW wall led to the wall-walk and parapets. A number of the tall merlins, pierced by short slits, survive, as does a corbel of a bartizan at N corner. There is a fine single-light trefoil-headed window in SW wall and a decorated projecting corbel on external faces of NE and SE walls. Though early in design, the castle is probably of 14th-C date: it was certainly still in use in 1574 when it was in the possession of 'Domynick Lynch' (Nolan 1901, 115) and was reputedly broken down in 1652 by Cromwell's forces (Hardiman 1846, 86-7). (O'Flanagan 1927a, Vol. 3, 265-6)