The Roman marching camp at Rey Cross is split by the A 66 trunk road. The camp is large having an area of about 20 acres. It is in the shape of a square, each side roughly 300 ft long. It is one of the best preserved of its type in the country and the visitor can easily trace its boundaries by foot. It has a number of entrances, each protected by a small rampart called a tutuli which protected against a frontal assault against the gate.

Its size shows that it was used as a temporary camp for a legion. This was very probably the resting place of the ninth legion, under the command of Cerialis, after the Battle of Stanwick in AD 72.