The park at Plas Berw lies to the south of Llangefni. It is laid out over the slopes of a ridge overlooking Malltraeth Marsh and part of the level ground at its foot which is just above the marshland. The views, such as they are, are across the marsh to the north-west. The site is an ancient one. Within the park is Plas Berw house, a seventeenth-century mansion (nprn 15001) and its immediate grounds (265407), and also the ruins of a fifteenth-century house (15000). Mentions of the name go back to the time of the Welsh princes in the early medieval period.

The park is rectangular on plan, long-exis north-east by south-west. It is bounded by the B4419 on the east, by field boundaries above the marsh on the west, and elsewhere by farmland and woodland. Much damage has been caused to the park by road and railway engineering. It is bisected by the railway line, built c.1841, which passes to the south and south-west of the house, on an embankment which crosses the drive on a bridge and continues northwards through the middle of the park.
The part-ruinous deer park wall forms the boundary on the south and south-west, replaced on the south-east by the modern road wall which continues along the south-east side of the 'Park Newydd' area. The rest of the boundaries are modern fences. The park wall stands to 1.5m-2m high in places and tapers from base to top; it is probably contemporary at least with the 1615 house, possibly with the fifteenth-century one.

A stream runs across the south-west end of the park, tumbling down the steep slope of the ridge in a series of small cascades. The stream bed has been altered to create one larger waterfall at the steepest point, and there are small pools and waterfalls both above and below this, possibly artificial. This may have been part of early nineteenth-century attempts at ‘upgrading’ the park which also included a folly and a 'hermit's cell'. The remains of a beech avenue along the drive, windswept but still imposing, may also date from this time. The area is now overgrown but the only ornamental planting in the park (recent) is here.
The orchard and kitchen garden lay to the north-east of the house (700312), and around them was woodland of which small remnants survive. Beyond is a rabbit warren, a wood and further areas of open park, one now containing a recent pond. There is no known record of when these park areas were added, but they never seem to have been walled. That they post-date the deer park is clear from a reference to 'Park Newydd' in 1754. The woodland enclosures around the garden are called, on an eighteenth- or early nineteenth-century estate map, 'Gwinllan coed', a reference to a possible former vineyard.

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, sheets: Anglesey XVIII.11 (editions of 1889 & 1900).

RCAHMW, 27 June 2022