The Civil Survey of 1654-6 records that Sir James Dillon, the first Earl of Roscommon, owned 210 acres here in 1640, which included not just the castle but also a ruined church, a stone house, a quarry and an orchard. Today, visitors can still trace elements of this historic estate: the remains of the stone house lie about 15 metres to the west, whilst the gatehouse sits 80 metres north and the parish church of Moymet 90 metres northwest.

The tower house itself is a rectangular structure measuring roughly 10.75 metres north to south and 8 metres east to west, with a projecting tower at its northeast corner. The ground floor features defensive double-splay loops in the eastern and southern walls, along with a single pointed light in the western wall, though much of the western and northern walls, including the original barrel vault, have been lost to time. The projecting tower likely had a twin at the northwest corner to house the main entrance and stairway, though this too has vanished. What remains reveals a sophisticated medieval dwelling: the first floor boasted large windows, a fireplace and a garderobe chamber, whilst the upper floors contained multiple fireplaces, windows of varying sizes, and additional garderobe facilities; all the hallmarks of a comfortable lordly residence.

The castle’s vertical arrangement tells the story of medieval domestic life, with each floor serving distinct purposes. The defensive ground level gave way to more comfortable living quarters above, complete with the medieval equivalent of modern conveniences. Though the parapet no longer crowns the structure and time has taken its toll on many features, including blocked windows and destroyed fireplaces, Moymet Castle remains an evocative reminder of the Anglo-Norman influence on the Irish landscape and the complex history of land ownership in 17th-century Ireland.