Across
- 2. Strategically located on the English Channel
- 3. Former Norman royal palace in Norfolk
- 5. Royal castle and prison on the Thames
- 6. Seat of the Duke of Northumberland
- 9. Site of King Edward II's murder in Gloucestershire
- 12. Ancient seat of the kings of Northumbria
- 15. Ruined royal fortress overlooking the North Sea
- 16. Site of a great medieval siege in Warwickshire
- 18. Restored medieval castle in West Sussex
- 19. Legendary birthplace of King Arthur in Cornwall
- 20. Ruined medieval border stronghold in Shropshire
Down
- 1. Mighty fortress in Gwynedd, Wales
- 4. Imposing Norman fortress in Kent
- 7. Picturesque castle in Kent
- 8. Norman fortress, now part of Durham University
- 10. Impressive border fortress in Cumbria
- 11. Royal residence in Berkshire
- 13. Mighty medieval fortress in Warwickshire
- 14. Roman fort turned medieval castle in Hampshire
- 17. Former prison and court in Lancashire