Considering the enormous number of castles in Ireland, it is perhaps surprising that only Dunsoghly has retained its original medieval trussed roof. This has survived because the castle, built around 1450, was continuously occupied until the 1870s by descendants of the same family, despite being cramped and uncomfortable by post-medieval standards. The topmost chamber of the south-west turret was used as a prison and is only accessible through an opening in the vault above it.There is a small chapel to the south bearing the year 1573 over the door, the Instruments of the Passion and the initials of John Plunkett and his wife Genet Sarsfield. On the west and south are remains of earthwork defences put up during the warfare of the 1640s. 4 km (2.5 miles) NW of Finglas off the Slane Road. NGR: O 118430.