The plaque is older than the house as it now stands, a relic of an earlier structure that was itself probably grafted onto a late-seventeenth-century predecessor. That sequence of building, burning, and rebuilding gives the place an almost geological quality, each phase depositing something legible in the fabric: a reused stone mullion in a basement window that may have been salvaged from a nearby castle, a brick arch inserted in 1825 to hold a water tank, bow ends appended in the late eighteenth century, and a two-storey dining room added in 1869 and removed again in the mid-1980s.

The house on the eastern edge of Doneraile was designed by Isaac Rothery for the St Leger family around 1730, though the core of what Rothery worked with may already have been a decade or more old. The entrance front, seven bays wide with a central three-bay breakfront, faces northeast across parkland and the Awbeg River, its Ionic columns and scroll pediment now absorbed into a balustraded porch added in the early nineteenth century. The house burnt in 1805, and reconstruction extended the garden elevation and reshaped the south-east front. Down in the basement there is a warren of corridors and rooms, brick wine vaults tucked into a corner, and those possibly reused castle stones set into a window of the south-western bow. An orangery recorded by Lewis in 1837 as having nine tall window openings in its south wall was partially dismantled between around 1970 and 1976, though a portion of its central masonry wall with three wide brick arches still survives. The Irish Georgian Society later restored the main house, which is now occupied by a caretaker.

The wider demesne, absorbed into Doneraile Amenity Park, retains a remarkable density of estate infrastructure. A ha-ha, a concealed ditch used to keep livestock out of formal grounds without interrupting the view, runs through the grounds alongside a deer park, impounded ponds, lime walks, and tree rings. A fish pond or canal some 370 yards long and 140 broad was noted by Smith in 1750; its upper section was supplied by a waterwheel that Arthur Young, visiting in the 1770s, described as an improvement on the Persian wheel, capable of raising a regular stream twenty-eight feet. The mound near a possible standing stone in the demesne is said to have been thrown up from the spoil of digging those ponds, and was subsequently used as a vantage point during hunts. Closer to the house, a farmyard building known as The Mill still contains a transmission shaft from horse-powered machinery, and the remains of a duck decoy lie about 450 metres to the east.