Duneagle Castle, Scottish Highlands The Season 3 Christmas episode takes place in part at Duneagle Castle in the Scottish Highlands, the family's annual vacation spot. The actual castle depicted in the episode is Inveraray Castle, located in Argyll, Scotland.
Urquhart Castle sits beside Loch Ness in the Highlands of Scotland, between Fort William and Inverness. Though extensively ruined, it was in its day one of the largest strongholds of medieval Scotland. It is near this castle that the majority of Nessie (Loch Ness Monster) sightings occur.