What US state is a royal palace in?

Question

What US state is a royal palace in?

Answer 1

Hawaii. Two monarchs governed from ʻIolani Palace in downtown Honolulu: King David Kalākaua and Queen Liliʻuokalani.

Edit - I'm a Canadian and I knew it too. lol

Answer 2

Hawaii was formerly a kingdom.

Answer 3

Can only be Hawaii as it was a kingdom at one point.

I'm a Brit and even I knew that off the top of my head.

Answer 4

If you count vice-regal residences, there's the palace in Williamsburg, VA, and, I think there may be one (Spanish) in Monterey, CA.