The Pen-heol-Adam practice work lies on enclosed land on a slight south-west-facing slope and is represented by a faint rectangular earthwork with rounded corners measuring 23.5m north-east to south-west by 20m. It is defined by a low bank 2.5m wide and and 0.2m high enclosing a dry platform slightly higher than surrounding ground, but there is no visible ditch. A likely entrance is in the centre of the south-east side. The site is crossed by a field boundary.
There are other practice camps on nearby Gelligaer Common and on enclosed and around its fringes.

D.K.Leighton, RCAHMW, 24 September 1991.