Oseosan Mountain is the highest mountain on the western coast of Korea, the highest one (790.7m) in Geumbukjeongmaek, at the edge of the Charyeong Mountains of the Baekdudaegan Mountain Range

It is a mountain that forms the boundaries of Boryeong-si, Hongseong-gun, and Cheongyang-gun, and embraces the natural beauty of thick forests and deep and clean water.

Seen from the top, one can watch waves of silver grass like a watercolor, the horizon of the West Sea, and the setting sun. With Seongjusan Mountain to the south, Gayasan Mountain to the north, Chilgapsan Mountain, and Gyeryongsan Mountain to the east, it is a mountain that allows visitors to see panoramic landscapes of the sea, sky, and land.

Oseosan is a mountain with many crows and magpies, and many places in Boryeong were named for the same reason.

Moreover, the mountain has rocks of fantastic shapes, twisted ridges, and a relatively flat top, making it popular among hiking enthusiasts and the general public.

In particular, it is called the lighthouse of the West Sea, as the guide to the western sea route. (By one account, it is called Oseosan because it looks dark. seen from Oeyeondo) It is famous for its ridges covered with silver grass in the autumn.