 The curtain walls enclose , making it the largest castle in Northumberland.The most prominent part of the castle is the Great Gatehouse, a massive three-storey fortification, considered by historians Alastair Oswald and Jeremy Ashbee to be "one of the most imposing structures in any English castle".Multiple rectangular towers protect the walls, including the Lilburn Tower, which looks out towards Bamburgh Castle, and the Egyncleugh Tower, positioned above Queen Margaret's Cove.