Llanidan Hall is situated in the south corner of Anglesey on the shore of the Menai Strait (nprn 15733). Gardens lie close to the house (265387) and these are partly bounded by a ha-ha which separates them from the outer parkland (700033). 

The ha-ha - a wall concealed from sight in a ditch - probably dates to the late eighteenth century phase of landscaping. It allowed an unimpeded view from the house down across the park to the Menai Strait and the (Romantic) mountains beyond. There were once two small stone bridges across its ditch and the western one survives.

At the bottom of the park a low bank hid the (un-Romantic) muddy foreshore from the house and two small plantations framed the vista. To the north of the house another ha-ha was built to separate the drive from the park. This is still intact, with an avenue of mature chestnuts and limes along its edge.
 

Source: 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)).

David Leighton & John Wiles, RCAHMW  14 February 2022