[4] The stone fort was built some time after the wall, in the usual playing card shape, with gates to the east, west and south.

Excavations between 1987 and 1992 showed an unbroken sequence of occupation on the site of the fort granaries, running from the late Roman period until possibly 500AD.

[citation needed] The granaries were replaced by two successive large timber halls, reminiscent of others found in many parts of Britain dating to the fifth and sixth centuries.

Unusually for an auxiliary fort, it also included an exercise building (basilica exercitatoria), perhaps reflecting the difficulties of training soldiers in the exposed site in the north of England.

Geophysical surveys detected vici (civilian settlements) of different characters on the eastern, western and northern sides of the fort.

[8] Approximately 600 metres east of Birdoswald, at the foot of an escarpment, lie the remains of Willowford bridge which carried Hadrian's Wall across the River Irthing.

The visitor centre features displays and reconstructions of the fort, exhibits about life in Roman Britain, the site's history through the ages, and archaeological discoveries in the 19th and 20th centuries.