Although sometimes in the shape of a parallelogram, Roman camps were usually rectangles formed by sets of ditches and ramparts, perhaps topped with wooden palisades. Corners were rounded as opposed to right angular, giving the troops inside more space to manoeuvre and fight. Contemporary authors described the layout of the buildings inside permanent forts (such as Bremenium) in great detail, but such rules were probably not followed in marching camps, where the majority of troops probably used leather tents and there were no permanent structures such as barrack blocks and granaries.
Marching camps were sometimes just built by a legion for a short stay, and possibly knocked down before they left. However, those along Dere Street seem to have been afforded a degree of permanence, if only because they were probably not under immediate threat and were in regular use when the army was active in the area.
Camps had at least four gates, usually with one in the middle of each side, although large camps might have two in the longer ones. Despite their name, these were just openings in the ramparts protected either by banks (tituli) built across them some yards outside the camp, or by extending the ramparts on one or both sides of the opening in a curve inwards or outwards. These were known as claviculae and they blocked direct access through the gate while leaving a gap at one side.