Some six trenches were excavated on the western side of Milfield Airfield in 1997. Two of the trenches revealed a criss-cross pattern of prehistoric ardmarks. A bigger area was then excavated and more ardmarks were found. They survived as narrow irregular grooves in the ground, spaced about 200mm to 400mm apart, and were roughly parallel to each other. This area of ardmarks is probably the most extensive yet discovered in Northumberland.