You have your origin state. For Japan (since this is a Japanese word), that would be the main island, the big one in the middle: Honshu. You'll have to know some minor Japanese geography for this. Go look at a map of Japan and study it over real quick to see where I'm talking about if you don't know already.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
What is the population of Honshu?
Mt. Fuji is located in Honshu.
I came from Honshu by ferry last night.