(Edited based on a comment. I should have read the question more carefully.)
I don't know that I'd say "in which" would be better in any case. I would say (1) the two mean the same and (2) "where" is less formal-sounding than "in which," though by no means is it overly informal.
And in the country case, as the commenter says, "in which" sounds a bit odd. Taking a few example sentences:
- I am in the house in which I was born
- I am in the town in which there was a hurricane
- I am in the country in which there were elections in April
- I am in the solar system in which the earth resides
It seems like, the larger the "place", the odder "in which" sounds. Honestly, I don't like "in which" in any of these cases personally. It sounds overly formal to me.