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Roman stronghold that passed into Welsh legend

Established nearly two millennia ago, this strategically-placed fort at the edge of the Roman Empire bustled with life for more than three hundred years.

Segontium was founded by Agricola in AD77 after he brutally suppressed a rebellion by the native tribe known as the Ordovices. Designed to hold a 1,000-strong regiment of auxiliary infantrymen, it was linked by Roman roads to the main legionary bases at Chester and Caerleon.

Thanks to excavated coins we know the Romans stayed until about AD394 – no other fort in Wales was held so long. Segontium not only controlled access to fertile and mineral-rich Anglesey but later helped defend the Welsh coast against Irish pirates.

Long after the final departure of the legions Segontium passed into Welsh legend as Caer aber Seint – ‘the fort at the mouth of the Saint river’ – mentioned in The Dream of Macsen Wledig, one of the ancient tales of the Mabinogion.

More about Segontium Roman Fort

Opening times

Daily 10am–4pm

Last admission 30 minutes before closing

Closed 24, 25, 26 December and 1 January

Free admission


Car park icon Dogs welcome icon Drone policy icon No smoking icon Venue hire icon

Parking is available on the main road adjacent to the monument for a small number of vehicles

Dogs on leads welcome to access ground floor levels of the site.

Please read our policy information about flying drones at Cadw monuments: read the guidance

Smoking is not permitted.

This site is available to hire for events, filming and exhibitions.


NCN Route No.8 (1km/0.6mls)

Contact us

Telephone 03000 252239


Constantine Rd, Caernarfon LL55 2LN

For contractors, educational visits and deliveries please ring 01286 675072
Rydym yn croesawu galwadau’n Gymraeg / We welcome calls in Welsh.