Seaton Law is a small fort situated on a rocky outcrop on the end of a ridge that is a continuation of the Garleton Hills to the west. Although the fort is only slightly raised above the surrounding land, it offers a 360 degree view over the area, with the important sites of Traprain Law and Berwick Law both visible in the distance.

With the bigger fort of Kae Heughs further to the west, it may be that Seaton Law was built as an outpost to offer an extra dimension of defence from an attack along the ridge. Just 250m or so to the north-west of Seaton Law was a second fort at Hanging Craig, now only visible as cropmarks.

The approach to the fort from the east slopes gradually and is steeper than it first appears. The top of the fort is wide and flat, and covered in tussocks of grass which make it difficult to identify any features below.

At the west end of the fort there appears to be a section cut off from the main body of the fort by what may be a wide ditch. However quarrying has taken place at this end – possibly for the building of Barnes Castle – and the depression may be associated with that rather than representing a true ditch.

Interestingly this fort is now listed as a quarry by the RCAHMS, having previously been designated a fort and marked on the OS map as such. However it certainly appears to be a fort, albeit a small one.