Portchester Castle (Latin name: Portus Adurni) is a Roman Channel Fort, considered by many as one of the finest Roman fortifications remaining in Europe.

The fort was built during the 3rd century to protect the southern coastline of Britain from Saxon raiders (part of the Saxon Shore) and occupies a commanding position at the head of Portsmouth harbour. The fort is square, enclosing an area of 9 acres (36,000 m²) with outer walls 20 feet (6 m) high, 10 feet (3 m) thick, 210 yards (200 m) long and constructed of coursed flint bonded with limestone slabs.

Unusually for a building of this period, the walls and bastions are complete except for the bastion in the south east corner which has been blanked off. The exceptional condition of the fort is probably due to its continued use, from the departure of the Roman Army right through to the 19th Century, when it was used as a gaol for prisoners of the Napoleonic Wars.

There is a small church within the grounds, next to the south-eastern corner.

The site is owned by English Heritage and is open to visitors.

External links

English Heritage