Nagayama Kofun is a keyhole-shaped tomb that was constructed adjacent to the outer moat of Nintoku-tenno-ryo Kofun [2-1], on the north side. It is thought to be related to Nintoku-tenno-ryo Kofun as a satellite tomb.
The mound length is 100 m, and both the round rear and square front parts are 10.3 m in height.
The construction period dates to the first half of the 5th century.