The tumulus was designated a National Historic Site in 1938 and re-designated as a Special National Historic Site of Japan in 2020 as part of the Sakitama Kofun Cluster.

As with the other keyhole-shaped tumuli in this cluster, the Atagoyama Kofun had a rectangular double moat.

A large number of haniwa have been excavated from this tumulus, including haniwa shaped as cylinders, "morning-glory", houses, horses, men with swords, and other male figures.

The burial chamber has not been excavated as the mound was in very poor repair and was in danger of collapsing.

Media related to Atagoyama Kofun (Gyoda) at Wikimedia Commons