The remains of a Norman castle with interpretation panels, an elevated viewing area and some seating is a main focus
of interest on the city wall trail. Leaflets on the trail are available at the information centre in Sun street opposite the cathedral's main gateway.

Canterbury Castle was established in the 1080s by the Normans and replaced an earlier motte and bailey fortification built at the nearby Dane John. The stone keep was largely constructed in the reign of Henry I (1100 - 1135) as one of three Royal castles in Kent. By the 13th century the castle had become the county gaol.

The castle enclosure re-used the Roman town wall as its southern boundary. Some reused Roman material may still be seen in the far corner close to the Wincheap pedestrian subway.