Mount Hyōno is estimated as an upheaved submarine volcano which erupted 3 million years ago with Mount Naki and Torokawa-daira highland. This mountain is the second highest mountain in Chūgoku Mountains, and also the second highest in Honshū west of Osaka Prefecture. This mountain is in the Hyōnosen-Ushiroyama-Nagisan Quasi-National Park. This mountain is also selected as one of the 100 untrodden areas in Japan.