Apparently that mountain used to be called "Yatsugatake".

There were several changes of leadership, and now it's Youkai Mountain...

I hate that goddamn mountain, swarming with all those tengu... So I was happy when Moriya Shrine arrived from the Outside.

I figured that if the wind priestess had a child, the mountain might fall under human control and the tengu be driven out... But that was not to be.

Humans ruling over the mountain just doesn't fit the idea of Gensokyo...