Plas Tan-y-bwlch mansion, an eighteenth-century house enlarged in the nineteenth (nprn 28687), is located towards the south-east boundary of its parkland 700107), on the north side of the Dwyryd valley in the Vale of Ffestiniog, and is surrounded by gardens (28688). From the house and its mainly informal gardens there are outstandingly beautiful views across the landscape, and conversely the house and gardens form a conspicuous and picturesque object within it. 

The walled garden adjoins the woodland garden, in the south-west corner of the garden area. It lies alongside the drive form the south-west. It is trapezoidal in shape, long axis south-west by north-east, with a chamfered south corner and a south-west extension.The date is uncertain though the area was enclosed by 1818-19. The late nineteenth century internal layout of glass and other structures and a well, has gone and the main part has now been cleared for a car park though the walls survive, except on the northeast.  The south-western extension is now the private garden of 'The Potting Shed'. A row of sheds along the south wall of the extension corresponds  with some buildings on early maps. Beyond the extension is the gardener's cottage which also served as the south drive lodge (300233).

The landscape within which the gardens lie is part of the Slate Landscape of Northwest Wales World Heritage Site, Component Part 5: Ffestiniog: its slate mines and quarries, slate town and railway to Porthmadog. Inscribed in July 2020. 
See nprn 700107.

Sources:
Cadw 1998: Register of Parks and Gardens of Special Historic Interest in Wales: Conwy, Gwynedd & the Isle of Anglesey, 274-81 (ref: PGW(Gd)31(GWY)).
Ordnance Survey 25-inch map, sheet: Merionethshire XI.8 (1888). 

RCAHMW, 25 April 2022