Raedykes probably dates from the late 1st century AD (Agricolan), though it has been argued that it could be Antonine (2nd century) or Severan (early 3rd century). The camp rampart (vallum) encloses the summit and eastern slopes of Garrison Hill (191m 628 ft), a prominent spur overlooking the valley of the Cowie Water, a small river draining into the North Sea on the outskirts of Stonehaven. The camp covered an area of about 93 acres (37 ha), and a computer model suggests that this would have been sufficient to house three full legions, or around 16,000 troops