Located in the border of 8 km east southeast of Sefuri mountain (bribe), Nakagawa Town in Fukuoka prefecture (Nakagawa) and Tosu city in Saga prefecture (Tosu). At the top of the mountain there are forests such as television and microwave relay towers, but the view from the observation deck is wonderful.The origin of mountain-name is two theories, one of which is that the villagers of the 5th year of the year (951) died of illness and the young monk called Takanobu who was worried that it saved this, 10,000 Lotus Sutra Although I made a great request of the sutra, I was annoyed by beautiful incarnation of white snake, day and night, finally lost to temptation, I could not fulfill my wish, and the sutra expired in 9000 copies. Villagers pitied death of Takanobu and said they had a temple built a shrine on the summit.Mt. Oyama is a mountain made of granite, but the summit of the mountain is grassy, and from the observation platform you can see the Chikushi plain.
背振山（せぶりやま）の東南東8km、福岡県那珂川町（なかがわ）と佐賀県鳥栖市（とすし）の境に位置する。山頂にはテレビやマイクロウェーブの中継塔などが林立するが、展望台からの景観はすばらしい。
山名の由来は二説あるが、その1つは、天暦5年（951）の天災で多くの村民が病死し、それを憂えた隆信という青年僧がこれを救わんと、法華経一万部読経の大願を起こしたが、日夜、白蛇の化身の美女に悩まされ、ついに誘惑に負け、願を果たせず読経は九千部に終った。村民は隆信の死を哀れみ、山頂に石祠を建てて祭ったという。
全山、花崗岩からなる山だが、山頂は草地状で、展望台からは筑紫平野を一望できる。