Penrhyn Park Boundary Wall (partly in Llanllechid community)

The Penrhyn Park Boundary Wall is a Grade II listed structure that encloses a roughly circular park. It is constructed from roughly coursed rubblestone, featuring two distinct bands sourced from the Cochwillan and other quarries, with a coping made of irregular Penrhyn Quarry slate slabs set on edge. The wall stretches approximately 11 kilometers in length and reaches a height of up to 4 meters at its tallest points.

On the west side, the wall extends from the Grand Lodge entrance along the main A 5122 road, passing Home Farm towards Bangor. It veers away from the road near the municipal cemetery, continuing north-east along the park boundary towards Port Lodge and Porth Penrhyn, which it skirts to the east before meeting the sea. To the east of Grand Lodge, the wall follows the driveway to the castle, with the estate village of Llanygai located immediately to its south. It connects to the road between the village and Tal-y-bont just west of the bridge over the Afon Ogwen.

East of the river, the wall enters the Llanllechid community, running past the lodge at the south-east entrance to the park. It crosses the Chester-Holyhead railway and continues north-east to join the minor road to Aber-Ogwen, passing on the west side of the road and meeting the sea again just west of the river. At this point, the wall returns to the Llandygai community, where it transforms into a sea retaining wall.