Plas Berw (nprn 15801) is located to the south of Llangefni, on the slopes of a ridge overlooking Malltraeth marshes to its west. It is notable for its early seventeenth-century complex of house and courtyard garden, which adjoins the ruins of an older house, the former Plas Berw (15800). The house and gardens are situated within a deer park (see 700311) which may date to the fifteenth century, and has some of its original wall still standing.
The park may be associated with the original house of about 1480 or else with the mansion of 1615. However, notices of the site pre-date the existing house and it is possible that the park is an earlier, medieval, creation. A barn, now ruined, in the north-east part of the park (at SH46817187) may be as early as the seventeenth century. There are some slight traces of possibly early nineteenth century landscaping. The stream near the southern boundary has been induced to cascade and there is a hermit's cell nearby.

Archaeological investigation has shown that the court associated with the 1615 house was originally laid out as a garden with a open central area framed by paths and borders. North of the house there are traces of a possible large walled garden, later subdivided into an orchard and kitchen garden. The seventeenth century gatepiers here are not in their original position. The wooded area beyond this garden was known as Gwinllan Coed, implying the presence of a vineyard. There was also a rabbit warren in this area.
The outbuildings and farmbuildings, including the coachhouse (406286), are early nineteenth century. A railway cuts through the park directly behind the house.

Sources:
Cadw 1998: Register of Parks and Gardens of Special Historic Interest in Wales: Conwy, Gwynedd & the Isle of Anglesey, 24-7 (ref: PGW(Gd)42(ANG).
Ordnance Survey 25-inch map, sheet: Anglesey XVIII.11 (editions of 1889, 1900).

RCAHMW, 26 June 2022