Key facts
- Operator
- Hampshire County Council
- Condition
- Ruin
- Access
- Free, open access
Pinpoint
North Warnborough, Hook RG29 1HQ
Possible Opening hours
Opening times change. Always check with the operator before you travel.
| Monday | Open 24 hours |
| Tuesday | Open 24 hours |
| Wednesday | Open 24 hours |
| Thursday | Open 24 hours |
| Friday | Open 24 hours |
| Saturday | Open 24 hours |
| Sunday | Open 24 hours |
The ruins of King John's octagonal keep, an unusual shape for a castle of its era, set beside the canal towpath. It's small — most visits take ten to fifteen minutes — and free, so it works best as a stop along a longer canal walk rather than a destination in its own right.
Worth the trip
The octagonal shape of the keep itself — a genuinely unusual design choice among surviving English castles.
Before you go
It's a short walk from the canal towpath, so combine it with a longer stroll; reviewers particularly recommend continuing on to the two nearby fords rather than turning straight back.
Reviewers consistently describe Odiham as a small, free ruin best enjoyed as part of a pleasant canal-side walk, with most visits lasting only 10-20 minutes at the castle itself. There are no notable complaints in this review set — the walk and setting are considered worth it even for such a compact site.
King John's octagonal keep, free access
“A fascinating medieval 'Castle' ruin. It's small for a 'castle'. You can stand inside and there are information plaques. Lovely walk to it by the canal.”— Louise Francis, visitor review
