The site of Carl Wark lies just within the Yorkshire side of the border with Derbyshire, rising out of the boggy centre of the impressive Hathersage Moor, in the Peak District National Park.
There are remains of a drystone revetment wall, on the northwestern end, may date to the Iron Age, still survives over 2 metres in height. It is around 40 metres in length. To the south of it, there is a single interned entrance, which is in a poor state of repair. The whole inner area of the fort covered around 1 hectare.
Carl Wark is of unproven origin, thought to be Iron or Dark age in date, though Bronze age artifacts are also close by, including the remains of a cairn, ring cairn and field systems. It could be that Carl Wark started even earlier, possibly during the Neolithic.
Only a single, small scale excavation has ever been conducted here and it proved to be inconclusive.