It is located in the Kyushu mountains at the northern end of Kumamoto Prefecture in the middle of Kyushu.
Oita Prefecture is bordered on the east, north, and west of the town.
Approximately 80% of the town area is covered with forests, and approximately 75% of the forests are artificial forests of Japanese cedar ("Oguni cedar").

The population is approximately 7,500 (2018).

The center of Oguni's industry has long been the forestry industry (Oguni cedar).
In agriculture, daikon production and breeding of jersey cattle, which were introduced in the late 1950s, are thriving.
The town also has many nationally famous natural hot spring facilities (Tsuetate Onsen/Waita Onsen).
In recent years, the number of stylish cafes and restaurants that take advantage of the natural environment has increased.