Caer Llugwy, or Bryn-y-Gefeiliau, is the site of a Roman fort in a loop of the Afon Llugwy near Capel Curig in Conwy, Wales.It is notable in that there has been little development in the surrounding landscape: the valley in which it is situated being much as it was 2000 years ago. It is a Scheduled Historic Monument. The remains are on private land.
From the conquest of Wales onwards the Romans attempted to contain guerrilla resistance in the highland areas by surrounding the mountains with a network of forts and roads in the valleys. Founded around AD 90, Caer Llugwy housed an auxiliary cohort of around 500 men who policed the local population and controlled communications through the Llugwy and neighbouring valleys.There is a possibility that the outpost was also intended to control mining operations in the nearby hills, hence its Welsh name: Bryn-y-Gefeiliau; "Hill of the Smithies".