Plas-yn-Llan is a substantial farmhouse platformed into a steep slope, situated on the western edge of the Hiraethlyn valley floor to the south of the village of Eglwysbach. It is notable for the survival of the structure of an interesting and unusual partly rock-cut walled and terraced garden of the late seventeenth century, probably created for the use of Sir John Wynn of Wynnstay in c.1684 when the status of the house was raised from mere farmhouse to gentleman's residence. 

The garden is of modest size and falls into two main areas: the level ground in front of the house and the steeply-sloping ground behind it. In front, to the east of the house, is a rectangular rubble stone-walled enclosure, 1.2m high. The interior is grassed over. Behind the house the garden is walled and terraced and has long fallen into disuse as a garden. It is now largely grassed over and grazed. Consisting of two enclosures, the main, larger, one is reached by a flight of rock-cut steps, now partly grassed over. The interior is terraced, the remains of flights of steps visible, and with a few trees. To the south of the main enclosure is a smaller one, surrounded by low rubble stone walls. The ground descends steeply to the east and is not terraced. The enclosure is grassed and planted with cherry trees; it is likely that it was always an orchard.

Sources:
Cadw 1998: Register of Parks and Gardens of Special Historic Interest in Wales: Conwy, Gwynedd & the Isle of Anglesey, 134-5 (ref: PGW(Gd)51(CON)).
Ordnance Survey second edition 25-inch map: sheet Denbighshire VI.10 (1900).

RCAHMW, 1 July 2022