The lands here were originally granted to Maurice de Prendergast by Strongbow, though by 1247 they had passed to Gerard de Roche, who held them from William Valence for five knight’s fees. The property’s ownership became more complex when Richard II granted much of the Valence lands to John de Beaumont in 1395, though the Roches retained their holdings. After Beaumont’s lands reverted to the crown in 1485, the Devereux family eventually took possession in the late 16th century, likely adding the upper storeys we see today.

The castle itself is a substantial three-storey structure with an attic, measuring roughly 15.8 by 12.65 metres, built with characteristic base-batter walls. Two barrel-vaulted chambers occupy the ground floor, each with its own round-headed entrance; the southwest doorway still features its original murder-hole overhead. The first floor comprises a single large chamber with fireplaces on two walls and what were once mullioned and transomed windows overlooking the river. A combination of mural and newel stairs provides access between floors, with the newel stair at the eastern angle continuing all the way to the attic. The upper floors display more elaborate features, including multiple mullioned windows with hood mouldings and distinctive diamond-shaped Jacobean chimney flues in the southwest wall.

Deeps Castle’s later history reflects Ireland’s turbulent 17th century; in January 1650, Cromwell’s colonels Cooke and Shelburne captured it from Phillip Devereux, who had owned 560 acres in the area. The property then passed to Francis Randall, a Quaker who famously aided James II during his flight into exile. The local Quaker community, the Edermine Meeting, gathered at Randall’s house until 1666, when they relocated to Forest near Taghmon. By 1726, the castle had passed to the Frayne family, probably through marriage, and they may have been its last residential occupants before the end of the 18th century.