Each milecastle on Hadrian's Wall had two associated turret structures. These turrets were positioned approximately one-third and two-thirds of a Roman mile to the west of the Milecastle, and would probably have been manned by part of the milecastle's garrison. The turrets associated with 'Milecastle 63 are known as Turret 63A (grid reference NY428593) and Turret 63B (grid reference NY422590). None of the turrets between Milecastles 59 and 72 were sought or identified prior to 1961, and the exact locations of turrets 63A and 63B have not been found.[3]