Orford Castle was built by Henry II to assert his Royal authority over the region, and in particular over Hugh Bigod, earl of Norfolk. The remarkable 21 sided tower with its three projecting square turrets, was completed in just two years (1165-7), and once stood within a curtain wall with rectangular towers and a twin-towered gatehouse (now all gone).

The remaining tower is unique in Britain. The circular interior contains many rooms on five floors, including kitchens and a chapel. From the top of the 27m tower there are great views of Orford Ness and the surrounding countryside.