Caer Gai is a Roman auxiliary fort situated near the southern end of Llyn Tegid (Bala Lake) in Gwynedd, occupying a low plateau commanding the upper Dee valley. It was established in the Flavian period, probably in the 70s AD during the campaigns of Agricola or his predecessors, and appears to have been abandoned around the early second century, with occupation roughly spanning c. AD 75–130. The fort covered approximately 1.7 hectares, suitable for a quingenary auxiliary cohort.
Source: Pleiades — A Community-Built Gazetteer and Graph of Ancient Places. View the Pleiades record →
Caer Gai was a key link in the network of forts controlling the mountainous interior of north-west Wales, sitting on the road running between Chester (Deva) and the western Welsh coast via Brithdir and Tomen-y-Mur. Its position guarded a natural east–west route through the Berwyn and Aran mountains, projecting Roman military authority into Ordovician territory.
The fort's rampart and ditch circuit remain visible as earthworks, with the present farmhouse standing within the defences; limited excavations in the twentieth century (notably by Gresham in the 1950s) identified timber internal buildings, a stone gateway, and produced pottery and tile, including stamped tiles attesting a garrison presence. No full-scale modern excavation has taken place, and the identity of the specific unit stationed there is not securely established.
Caer Gai is a Roman auxiliary fort situated near the southern end of Llyn Tegid (Bala Lake) in Gwynedd, occupying a low plateau commanding the upper Dee valley. It is recorded in the Pleiades gazetteer of ancient places as a fort site from the Roman period in Britain.
Caer Gai is classified as a Roman fort — a military site in the Pleiades ancient world gazetteer. Roman Britain's archaeology encompasses thousands of sites ranging from legionary fortresses and marching camps to villas, temples and towns.
Several Roman sites lie within a short distance, including Llanfor (7.6 km), Tomen y Mur amphitheatre (18.5 km), Tomen y Mur Roman bath house (18.5 km). Aubrey Research maps over 2,200 Roman sites across Britain, drawn from the Pleiades ancient world gazetteer.
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