Roman remains were encountered in Tremadoc in the later part of the nineteenth century. Remains of a Roman bathhouse were excavated in 1908. This building produced second to fourth century material. The baths comprised a range about 20m east-west by 9.0m with additions on the north & south. It was terraced into rising ground on the north.
Further Roman remains have recently been excavated 200m to the north-west (NPRN 405435).

Sources: Breese & Anwyl in Archaeologia Cambrensis 9 (1909), 473-94
Daniels in the Bulletin of the Board of Celtic Studies XXIII.2 (1970), 187-90
Kenny in Archaeology in Wales 45 (2005), 25-32

Possibly the source of or inspiration for, the 'Roman Altar' recorded roughly 1.0km to the east (NPRN 309647).

J.Wiles 15.02.05

More detailed research on the environs of the bath house was carried out when more than 400 stacked slates and a kiln was excavated in advance of the Tremadog bypass, known as the Llidiart Ysbyty site, in 2010-11 (Parry and Kenney 2012, 120-3). It is thought likely the slates were associated with the nearby remains of a bath house excavated in 1908, possibly associated with a nearby mansio.

T. Driver, RCAHMW, Oct 2017

Reference:

Parry, L. W. and Kenney, J. 2012. Archaeological Discoveries along the Porthmadog Bypass. Archaeology in Wales, 52, 113-132