Castling across a checked square

Forgive me if this question seems obvious to you all: Can a Knight prevent a King from castling if one of its potential moves is a square between the opponents King and Castle? I'm guessing yes, but as it's not a "direct line of fire" (like with a Bishop, Queen, etc) I'm confused. I have never had such a problem before!

Thanks

Just to be clear it's not if the square is in between the king and rook, it's if the king has to pass through/land on an attacked square.  So the answer is yes, a knight can prevent castling, it doesn't matter what the piece is, as long as the square is threatened.

I clarified the first part because another common question is "can the rook pass through a threatened square as long as the king doesn't" and the answer is yes.  It only ever has to do with the king passing through a threatened square, regardless of what piece is threatening it.

White to move can castle either direction, black to move can't castle at all.

Wow, that was really quick guys - thank you! I guess I should have attempted "chess-speak" and said upfront that my Knight would be on e6, hovering right above the black King(and unthreatened!)  He's not quite there yet in this game I am currently playing, but is 2 moves away and knowing the answer to this helps me greatly.

Feel free to have a look at the positioning in my game if my explanation doesn't cut it. (But please - no advice on what I should do here - I need to play my own games, I merely wanted to clarify a rule)

Thanks again guys!

Pete

Oh, and all this hinges on whether my opponent even wants to swap queens! That may not even be his intention!

And yes, orangehonda's illustration was brilliant, and made it crystal clear. Thanks for the work that obviously was put into that, mate.

Update: My opponent did swap Queens, as anticipated, and my move in with the Knight had the desired effect of preventing castling, so I am glad I came here and sought advice on the rules. As of today, the game is still in progress, but looking promising, possibly due to this particular combination of middlegame moves...