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Segontium Roman Fort is a Roman auxiliary fort located near Caernarfon in Gwynedd, Wales, established in the late first century AD as part of the Roman conquest and consolidation of Wales. The fort was constructed around AD 77-78 under the command of Agricola and served as a crucial military installation for controlling the northwestern region of Roman Britain and maintaining supply lines to Anglesey. The site preserves substantial earthwork remains including the characteristic playing-card shaped layout typical of Roman forts, with visible defences, internal structures, and evidence of occupation spanning roughly three centuries. Segontium remained in use until the early third century AD, representing one of the most important Roman military establishments in Wales and providing significant archaeological evidence for Roman frontier administration and military logistics in the province.
Segontium Roman Fort is a scheduled monument protected by Cadw under reference CN006. View the official record →
Segontium Roman Fort is a Roman auxiliary fort located near Caernarfon in Gwynedd, Wales, established in the late first century AD as part of the Roman conquest and consolidation of Wales. It is designated a Scheduled Ancient Monument by Cadw under reference CN006.
Segontium Roman Fort dates from the roman period, and is classified as a fort. It is one of over 32,000 scheduled monuments protected across the UK.
Segontium Roman Fort is a Scheduled Ancient Monument, legally protected by Cadw — the body responsible for designating and safeguarding heritage sites in Wales. The official designation reference is CN006.
Several scheduled monuments lie within 10 km, including Enclosed Hut Circle Settlement West of Votglas (8.7 km), Blaen y Cae Slate Quarry (8.7 km), Pen Y Bryn Quarry and tips (8.8 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Segontium Roman Fort's history, each drawn from the record and mapped to the exact spot:
Every location is different. Not every section appears for every place, only what the historical record actually holds turns up in a report.
Segontium Roman Fort stands on Llanvirn Rocks (Undifferentiated), bedrock that formed in the Whiterock. The rock here is mudstone, siltstone and sandstone.