There were seventeen forts along the wall averaging about five miles between them. Seven were built astride the wall and six were attached to its southern side. The forts were of two sizes: two and a half acres, the size required to accommodate 500 men and 5 acres, the size required to accommodate 1000 men.
At regular intervals, approximating a mile, the Romans constructed milecastles with dimensions of about 70 x 60 feet and attached them to the wall. They were of a size to accommodate 100 men and had gates to the north and south.
Turrets were located between each milecastle at 1/3 and 2/3 of the distance between them. Each turret was about thirteen feet square internally and contained a staircase used to climb to the rampart on the top of the wall. There were no stairways on the wall except at forts, milecastles, and turrets.