Ishibutai kofun (石舞台古墳) is a stone kofun or tumulus of the Asuka period in the east of Shimanoshō, Asuka, Nara Prefecture, Japan. The kofun is believed to be the tomb of Soga no Umako. It occupies an area of 27 m2 (291 sq ft), and is the largest known megalithic structure in Japan. The kofun is also known as the Ishibutoya (石太屋) Kofun. It is located 5 km from Tanzan Shrine.

Nara Prefecture is a prefecture of Japan located in the Kansai region of Honshu. As of 2020, Nara Prefecture has a population of 1,321,805 and has a geographic area of 3,691 square kilometres (1,425 sq mi). Nara Prefecture borders Kyoto Prefecture to the north, Osaka Prefecture to the northwest, Wakayama Prefecture to the southwest, and Mie Prefecture to the east.