The Roman fort on the hill above Caernarfon that held down north-west Wales for close to three centuries
Open to visitorscheck opening times and admission before you go
Substantial ruinsruined, but plenty survives above ground
Long before Edward I raised his great castle by the water, the Romans held Caernarfon from the hill just above it. Segontium — the fort’s Roman name, taken from the River Seiont that runs below — was built around AD 77, when the army pushed into north-west Wales and across to Anglesey. Auxiliary troops rather than legionaries were stationed here, guarding the coast with the mountains at their backs, and the fort stayed in use unusually late, into the closing decades of Roman Britain in the fourth century. What you see today is the fort’s ground plan laid out at ground level: foundation walls, gateways and the outlines of the barracks and headquarters.
Cadw looks after Segontium, and it is free to walk round. The separate Segontium entry covers the same ground, and it is an easy walk downhill to Caernarfon Castle and the walled town, where the Wales Coast Path passes through. The mountains of Eryri, better known as Snowdonia, rise to the south-east.
