The fort at Castleshaw, constructed from turf and timber, was built around 79 and guarded the York to Chester Roman road. Due to the site's protected status as a Scheduled Ancient Monument it has not been possible to excavate the fort, however previous trenches have demonstrated that the fort had two phases to its construction. The location of the fort's granary, stables, the "principia" (headquarters), the "praetorium" (commander's tent), and six long narrow buildings which are possibly workshops or storerooms are all known. The fort was small, would probably have been home to around 500 soldiers of an auxiliary cohort, and fell out of use during the mid AD 90s. Rather than allow the defences to fall into potentially hostile hands or be used against Rome, the fort was slighted.