This area is dominated by the huge Dinorwig quarry, which lies at the foot of Snowdon not far from the Medieval Dolbadarn castle, prominently located between the two glacial lakes, Llyn Peris and Llyn Padarn. The scale of the quarry workings can be appreciated by the view over Llyn Peris.
Quarrying for slate was started by local partnerships from around 1700. However in 1808 the Vaynol Estate began to work in partnership with an experienced quarry manager from the English Lake District, William Turner, and took it over directly in 1820.
Dinorwig was thereafter developed like its neighbour Penrhyn, as a quarry under the direct control of the estate on which it was situated, and came to rival Penrhyn in size and output.
Initially transport of slates to the harbours at Caernarfon and y Felinheli (Port Dinorwig) was by horse and cart as well as by boat across Llyn Padarn.
From 1825 the quarry was served by a railway based on the design of Penrhyn quarry’s original railway of 1801. This was replaced in 1842 by a railway intended for steam operation.
In 1870 a major re-organisation of the quarry was completed, involving the construction of a new series of inclines, and the building of a large quadrangular workshop at Gilfach Ddu to service its maintenance needs. The scale of the workshops and its architectural ambition suggest that part of its purpose was to emphasise the landowner’s resources and social prestige. A state-of-the-art hospital was also built nearby around 1863, prominently located to emphasise the estate’s philanthropic intent.
Settlement and accommodation for quarrymen includes barrack buildings within the quarry. The conserved Anglesey barracks were built for labourers who stayed by the week in the quarry, as well as houses for senior employees. Quarrymen and their families had been settling on the common land to the north of the quarry since the 18th century, and resented the enclosure carried out by the Vaynol estate from 1806 to 1814. The estate’s policy thereafter was to settle them on plots of enclosed land and to encourage them to build their own dwellings. Those who chose to reject this settled on nearby freeholds, where they built the villages of Deniolen and Clwt y Bont.
The independent spirit of the quarrymen is also exemplified in Craig yr Undeb, ‘Union Rock’, their traditional meeting-place, where the North Wales Quarrymen’s Union was proclaimed in 1874.
The quadrangular workshops, little changed since 1870, now form the Welsh Slate Museum. The incline systems which brought the slate down to this point survive intact, and one has been restored to working order. Quarry locomotives haul tourist trains along part of the re-laid track-bed of the quarry railway of 1842. The hospital has been re-opened as a visitor attraction by Gwynedd Council. Much historic machinery survives in the quarry itself.