Mount Okue (1644 m) is the highlight of Sobo-Katamuki Quasi-National Park, known as the last unexplored land of Kyushu island. The mountain is characterized by a series of craggy walls, sometimes distinguished with names like Kozumi-daki, Nimai-daki, Sode-daki, Okue-daki, etc. (-daki refers to a rock wall), and valleys enveloped in lush primeval forests.The mountain has several trails, each of which entertains visitors from inside and outside the prefecture with seasonal beauties like Akebono-tsutsuji (azalea) in spring and autumn foliage.
Okue mountain system used to be an underground dike formed through volcanic activities, which later emerged on the surface after crustal uplift and erosion. Mountains made of the large granite porphyry dike, such as Hokodake, Mt. Hiei, Yahazudake, Mt. Mukabaki, etc. are seen surrounding Mt. Okueyama.