The Loch Ness Castle Blown Up by Its Own Garrison — and Why They Did It

The garrison inside Urquhart Castle had held the walls for years. They had survived sieges, raids, and the bitter Highland winters. Then, in 1692, they packed the gatehouse with gunpowder and walked away. What they left behind is one of the most dramatic ruins in Scotland.

Built to Control a Loch That Connected Two Coasts

Loch Ness is not just deep — it is also long. It stretches 23 miles through the Great Glen, the geological fault line that cuts Scotland in two from east to west.

Whoever controlled Loch Ness controlled movement between the coasts. That made the rocky promontory at Strone Point, jutting out into the loch, one of the most valuable pieces of land in the Highlands.

Urquhart Castle was built there to protect that advantage. The first fortifications date back to the 6th century, though the stone castle took its recognisable form in the 13th century.

Six Centuries of Sieges and Surrenders

Edward I of England seized Urquhart in 1296. The Scots won it back. Then lost it again. Then won it back once more.

Robert the Bruce finally took control in 1307. But peace did not last long.

The MacDonald Lords of the Isles raided Urquhart repeatedly through the 15th and 16th centuries. In 1545, they sacked it so thoroughly that the castle never fully recovered. The garrison struggled to maintain the walls and towers after that point.

It is a pattern repeated across the Highlands. Scotland’s ruined castles each carry these scars in their own way — every crumbled wall is the end of a particular story.

The Jacobite Rising Changed Everything

By the late 1600s, Scotland was caught up in the Jacobite rebellions — the uprisings that tried to restore the Stuart kings to the British throne.

The government in London needed loyal garrisons holding key Highland strongholds. Urquhart was one of them.

A small government force moved in. They repaired what they could. They watched the loch. They waited.

The Battle of Killiecrankie in 1689 shook the Highlands. Jacobite forces were moving. The garrison at Urquhart found themselves increasingly exposed.

The Night They Lit the Fuse

When the order came to abandon Urquhart in 1692, the garrison faced a problem.

If they simply left, Jacobite forces could move straight in and use it as a base. A castle that strong, in that position on the loch, was too useful to leave intact.

So they packed the gatehouse with gunpowder.

The explosion brought down the main gatehouse and collapsed large sections of the curtain wall. The Grant Tower — the tall five-storey tower house added in the 1500s — survived because it was built more solidly. But even it lost parts of its upper structure to the blast.

They did not destroy Urquhart out of spite or failure. They destroyed it so no one else could use it. It was a cold, deliberate act of denial.

It is a strategy Scotland’s defenders understood well. Dunnottar Castle on the Aberdeenshire coast faced a similar moment — its own defenders blowing sections apart to deny them to the enemy.

What the Grant Tower Still Tells You

Standing at the top of the Grant Tower today, you understand exactly why this spot was worth fighting over for five centuries.

The view stretches the full length of Loch Ness in both directions. The water is dark, deep, and unnervingly still on a clear morning. You can see every boat on the loch, every mile of shoreline, the mountains above Fort Augustus at the far end.

The garrison who held this tower had perfect visibility over everything that moved in the Great Glen. That is exactly what made it so worth holding — and so dangerous to leave behind.

Visiting Urquhart Castle

The castle is managed by Historic Environment Scotland and is one of the most visited historic sites in the country. The visitor centre includes a short film showing the castle as it would have looked in its prime — watch it before you walk the grounds.

The best time to visit is early morning, before the tour coaches arrive from Inverness. The loch is glassy and quiet, and the ruins feel larger when you have them almost to yourself.

There is also a full-size reconstructed trebuchet on the grounds. It was built as an educational feature, but it is genuinely impressive and very photogenic.

A Different Kind of Castle Story

Most castle stories end in defeat — the siege that finally broke through, the fire that consumed the hall.

Urquhart’s story ends in a choice. A deliberate decision made in a cold dawn in 1692, by soldiers who understood that sometimes keeping something out of enemy hands means destroying the thing you have spent years defending.

The ruins they left behind are magnificent. Stand among them, look out over Loch Ness, and you will feel exactly why those walls were worth a fuse.