A purpose-built slate-port on the Menai Straits built between 1790 and 1855, on the site of a pre-industrial landing point and proto-harbour, which reflect the scale of output from Penrhyn Slate Quarry (NPRN 40564) and the resources which the owning family could invest in the transport and export of slate by sea. Its character as both an industrial harbour and as an estate port is evident in the quality and presence of its structures and buildings. Its proximity to Penrhyn Castle and Park (NPRN 86640, 16687) and its evident functional linkage to the railway systems (546003) illustrate its role within a complete industrial-cultural landscape from the source of the slate to its onward sea-journey.   

Port Penrhyn lies at the east end of the Menai Strait that separates Anglesey from mainland Wales, adjacent to the town of Bangor and to Penrhyn castle, and was the main shipping point for Penrhyn slate from the late eighteenth century to the twentieth. The river Cegin enters from the south, and the site is known to have been used for shipping by the sixteenth century.

The earliest known shipping point for slate was the pool upstream of the confluence where a plan of 1768 shows a road approaching from the east with a possible quay alongside. In 1790 Benjamin Wyatt designed stone quays with a small stone pier and a warehouse at the mouth of the Cegin river; a further small quay was constructed by 1803, lengthened in 1828-1830. In 1855 further construction resulted in the present extent of the harbour.

Port Penrhyn was initially served by the quarry road, then by the horse-drawn railroad of 1801, by a siding from the Chester & Holyhead Railway in 1852, which enabled slates to be distributed by the national rail network as well as by sea, later by the steam-worked narrow-gauge Penrhyn Quarry Railway from the 1870s.

Port Penrhyn remains in use as a commercial harbour and for pleasure craft, and occasionally exports some slate. Structures include the port-house office of the 1840s, the circular loaders’ privy, the very early (possibly late eighteenth century) warehouse, now the head-quarters of an organisation assisting disabled and disadvantaged people, the two-road locomotive shed for the quarry railway (1.3), and the shed for the quarrymen’s train.

This site is part of the Slate Landscape of Northwest Wales World Heritage Site, Component Part 1. Penrhyn Slate Quarry and Bethesda, and the Ogwen Valley to Port Penrhyn. Inscribed July 2020.

Hannah Genders Boyd, RCAHMW, January 2022

Sources:

Louise Barker & Dr David Gwyn, March 2018. Slate Landscapes of North-West Wales World Heritage Bid Statements of Significance. (Unpublished Report: Project 401b for Gwynedd Archaeological Trust)

Tirwedd Llechi Gogledd Orllewin Cymru / The Slate Landscape of Northwest Wales. Nomination as a World heritage Site (Nomination Document, January 2020)

Wales Slate World Heritage Site https://www.llechi.cymru/