The tumulus was designated a National Historic Site of Japan in 1936, with the area under protection extended in 2004.

The coastline during the Kofun period is estimated to have reached about ten kilometers inland from the present site; however, from ancient and medieval times land reclamation gradually progressed due to sedimentation of the Yahagi River.

The hills within two kilometers around the old burial mound are formed of gabbro, and the stones covering the kofun are almost entirely gabbroic.

The tumulus was covered in pine forest during the Edo period and was not recognized as a kofun until after the start of the twentieth century.

The first and second ties were formed by cutting and contouring the natural hill, and the uppermost level was added as an embankment.