Here we have an overview of Castle McDuck and the approach of the McDuck party to the grounds. Pretty barren, huh?

There is of course, the question "how many castles did the McDucks have"? There are at least two highly authentic sites. Perhaps the best known are the ruins in a story called "The Hound of the Whiskervilles", where Scrooge and his nephews are searching for the last surviving example of the tartan of the extinct McDuck clan. It was an effective and creepy story drawin in the early 60's, but the castle itself is a minor element. On the other hand there is the 40's epic, "The Old Castle's Secret". In this story, Scrooge's fortune has not yet acheived its superhuman proportions, and Scrooge himself is facing bankruptcy unless he can find a legendary lost treasure in the walls of his ancestral castle. This Castle McDuck is a far more imposing structure. Though inhabited by a single caretaker, it is in effect abandoned. The catch is, the treasure may be guarded by a ghost. And did I mention it was lost? Scrooge has one advantage previous treasure hunters lacked, however... an x-ray machine. Unfortunately, there's not only a treasure, but the ghost is real too...

There have been other lesser Castle McDucks mentioned in minor Duck stories, but none I remember seem canonical. In my picture of McDuck history, the clan must have had more than one castle, and the two described above are legitimate cases. I've invented one more Castle McDuck, though, by far the oldest as it was build on a Roman stronghold in the south of Scotland, eighteen centuries ago.

At top, centre of the castle (in this view) is the movable alter that leds to an underground passage. The passage winds under the castle, taking advantage of natural caverns, and exits from the vale at bottom right of the Castle wall. At first, neither yields to the Duck parties attempts to enter. (One of the lads discovers a bent, bronze coin in a crack in the rock wall, though, that proves there is a passage beyond.)

See also:
http://www.furaffinity.net/view/718792/
http://www.furaffinity.net/view/718763/