Llanidan Hall is situated in the south corner of Anglesey on the shore of the Menai Strait. Its park had origins in the early seventeenth century, contemporary with the house (nprn 15733), though the present landscaping dates from the period 1783-1816. It is a small but well-preserved landscape park in an exceptional position on the Menai Strait, with well-framed views to Snowdon. Its sophistication, with a sea shore bank and fine ha-ha, suggests that a professional landscaper may have advised on the layout. The site is an ancient one which incorporates a circular churchyard with yew trees, around the medieval church of St Nidan (43637), and nearby is St Nidan's holy well (32166).

The park is a triangular area fanning out to the south-east of the house and garden, sloping gently down to the edge of the Menai Strait. Park and grounds were walled from the start. The park is in three enclosures, the north-eastern two formerly one. The small stream fed by St Nidan's well runs down the one constant internal division. Several small, walled plantations of mixed deciduous trees survive around the edges of the park. Towards the sea there are two plantations on the sea edge flanking the central axis so that they frame the pristine view of the Strait and Snowdonia from the house and garden. The ha-ha separating park from garden was built in the early nineteenth century (15734), and a bank at the bottom of the park enhanced the view by concealing the muddy foreshore. In 1900 the enclosures were well planted with individual trees but most of these have now gone. The layout of the early park was formal. Although much of it was swept away by the later landscaping one of its main features, the central axis from the house down to the Strait, has always been maintained. On the shore, in a plantation, is the boathouse. To the south-west of the Hall, near the west margin of the park, a cruciform avenue has recently been planted (air photos). 

The house is approached from the north from an entrance and lodge on the A4080, along a drive that is now a public road. The drive close to the house was separated from the park by a ha-ha. A second drive from Brynsiencyn approached from the west.

Gardens and grounds, including a walled garden, lie around the house on its south-west and south-east sides (265387; 15735). 

Sources:
Cadw 1998: Register of Parks and Gardens of Special Historic Interest in Wales: Conwy, Gwynedd & the Isle of Anglesey, 18-22 (ref: PGW(Gd)46(ANG)).
Additional notes: D.K.Leighton

David Leighton & John Wiles, RCAHMW 14 February 2022