The fort was built between 120 and 138 on a rocky spur, and was initially garrisoned by a detachment of the Cohors IV Delmatarum from the Dalmatian coast (in modern Croatia).
It is in the civil parish of Eskdale, the unitary authority area of Cumberland, and the ceremonial county of Cumbria.
[2] The fort was built on a rocky spur giving a superb view over the River Esk in both upper and lower Eskdale, and protecting Hardknott Pass.
[5] Outside the square of the fort are the remains of the bath house below it (which has a rare circular sudatorium or sweating room), and the levelled parade ground above it, which is considered to be the finest surviving example in England.
The English Heritage online ‘History of Hardknott Roman Fort’ suggests that the parade ground would have been large enough to train horses there (cf.