This would be true, if "hihao" was a word in Japanese, and it meant "king." Unfortunately, this is not the case.
"King's Mountain" is 王の山 (ou no yama). Alternatively, you could say 王様の山 (ousama no yama) if you wanted to be more polite and use an honorific on the word "king," or you could even coin your own word with 王山 (which would probably be pronounced ouzan).
magevampjoe's suggestion, kokuou no yama (国王の山), literally means "mountain of the king of the country," and sounds a bit too literal for the name of an actual place.