Achasan is a mountain that sits between the counties of Gwangjin-gu and Guri in South Korea. It has an elevation of 287 m.
As you walk down towards Mt. Achasan from the summit of Yongmasan, you will find the ruins of a small fort of the Goguryeo era built at a strategic point overlooking the area of Jungnangcheon Stream. On the way up, you will find numerous observation platforms from which one can see a great view of some of the landmarks of Seoul such as the Hangang Bridge, Mt. Namsan, 63 City building, and Gangnam COEX.
There is an extensive system of trails on Achasan/Yongsan mountains with numerous entrances. In general, people start their hike from Mt. Yongmasan and go down to Mt.
Wikipedia https://en.wikipedia.org/wiki/Achasan
Address South Korea
Coordinates 37°34'16.045" N 127°6'15.661" E