The Atagoyama Kofun (愛宕山古墳) is a kofun burial mound located in the Atago neighborhood of the city of Mito in Ibaraki Prefecture in the northern Kantō region of Japan.

The tumulus is well-preserved, but the moat has mostly been filled in and is occupied by private residences.

[2] The interior of the tomb has not been excavated, but fragments of Sue ware pottery have been found in the vicinity in 1978 survey.

From the style of the haniwa it is believed to have been built in the early 6th century as the tomb of Takekashima-no-mikoto, the Kuni no miyatsuko of the "Nakanokuni", whose territories existed on either side of the Naka River.

[2] The tumulus is one of a cluster of kofun in the vicinity, which were not accorded protected status.