It is one of only three octagonal keeps ever built in England.
The castle was used as a prison for David II, King of Scotland, for 11 years starting in 1346.
King John utilized the site as a base to hunt in the expansive royal forest of Odiham.
The castle foundations were rediscovered and excavated during major archaeological works in the 1980s.
The site is strategically positioned on a promontory overlooking the River Whitewater.
Odiham Castle, also known as King John's Castle, is one of the few remaining octagonal keeps in the United Kingdom. Built between 1207 and 1212 by King John, this 13th-century hunting lodge served as a royal retreat in a royal deer park. The site was one of the last points of resistance against Prince Louis of France during the Baron's War in 1216. King John stayed here shortly before setting out to sign the Magna Carta at Runnymede in 1215. The ruins consist primarily of the stone foundations of the octagonal keep and surrounding earthworks. It survived a two-week siege by French forces before the garrison eventually surrendered. Over the centuries, the structure fell into disrepair and was largely dismantled for building materials. It is managed by Hampshire County Council and maintained as a public heritage site for pedestrians. The site remains a protected Scheduled Ancient Monument.
From the wooden footbridge over the Basingstoke Canal, which provides a clear framed view of the castle ruins across the water.
Wear sturdy, waterproof footwear as the surrounding meadow paths can become extremely muddy.
Bring insect repellent during the summer months as the riverbank area attracts significant midge populations.
The site is entirely outdoors with no visitor center or amenities, so bring your own water and supplies.
Attempting to visit after heavy rainfall when the surrounding meadow often floods, making the site inaccessible.
Keep dogs on a lead to protect local livestock and wildlife; do not climb on the fragile masonry walls.
