Hensol Castle mansion, a house with seventeenth-centry origins but remodelled and extended from c.1735 onwards (nprn 18963) is situated in rolling countryside on the west side of the Ely valley, to the south of Pontyclun. The mansion lies towards the eastern side of a medium-sized, roughly rectangular landscape park. The park was developed from the mid-eighteenth century onwards, with a major phase of ornamentation during the 1840s. The mansion is now used as a hospital (since 1927) and hospital buildings have been erected on parts of the estate.

The park is orientated north-east by south-west on rolling ground, the highest part being a ridge at the west end. The main entrance is in the north-east side of the park, flanked by incurving iron railings on stone plinths ending in square stone piers, rubble stone boundary walls either side. To the north is Bottom Lodge (18916). The drive runs westwards over a gently arched stone bridge (24124) and is flanked by mixed trees, curving south-west towards the east front of the house. From Mountain Lodge, on the south, a drive leads to a complex of hospital buildings south of the house, with branch drives flanked by beeches and copper beeches.

The centre of the park is occupied by a large lake which lies just west of the house. On an island near its west shore is a turreted folly (96337). To the east of the house a smooth grass slope is dotted with specimen trees, cedars and horse chestnut, and below are playing fields. Beyond is an inverted S-shaped pond (Mill Pond). The park has shrunk on its western side which once included the whole ridge as far west as a lane beyond Kennel Grove, with a number of clumps on the ridge top. These have now all gone. The far western side is now purely agricultural, while the parkland to the immediate west and south of the lake is mostly in use as a golf course on which there has been some new planting. Nearby Llwyn-yoy Pond is of some antiquity, appearing on the 1877 map.

Gardens lie around and to the north of the old mansion (see 265778 & 700162).

Sources:
Cadw 2000: Register of Parks and Gardens of Special Historic Interest in Wales, Glamorgan, 246-9 (ref: PGW(Gm)41(GLA)).
Ordnance Survey First Edition 25-inch map, sheet: Glamorgan XLII.5 & 9 (1877).

RCAHMW, 13 May 2022