Iron Age univallate promontory fort surviving as an earthwork. Kelsborrow Castle an Iron Age univallate promontory fort with
steep natural slopes to the South-West and South-East. An earthen rampart with an outer ditch encloses the North side.
Both have been much reduced and spread by the plough. Where best preserved, to the North-East, the rampart is 25.0m in width, 1.0m in height internally and drops 1.7m to the foot of the ditch, which is 15.0m in width and averages 0.3m in depth. The North-West end of the rampart has been completely ploughed out.
The original entrance was probably around the south-eastern end of the rampart, directly above steep natural slopes. On the North side, there is a waterfilled pit on the line of the ditch and the rampart has been reduced opposite it almost to ground level.