Sagiyama Castle, Japanese castle ruins in Gifu, Japan.

Sagiyama Castle is a ruined castle on Mount Sagi, a 68 m hill in Gifu, not on Mount Kinka. Its summit holds a stone marker and surviving earthworks: low earthen ramparts and traces of moats. In 1964 quarrying for the Tōkaidō Shinkansen and Meishin Expressway cut away part of the hill and exposed stones interpreted as foundation stones.

Satake Hideyoshi built Sagiyama Castle between 1185 and 1190. It became a branch castle of the Toki clan after they built Kawate Castle in 1353. In 1548 Saitō Dōsan handed it to his son Saitō Yoshitatsu, and it was abandoned after Dōsan's death at the Battle of Nagaragawa in 1556.

The castle is remembered for Nōhime, born in 1535 to Saitō Dōsan and Lady Omi; in 1549 she left here to marry Oda Nobunaga of Owari, which earned her the name Sagiyama-dono. Dōsan retired to the castle in 1548, and the site is now a park with a stone marker near the summit.

The site is on Mount Sagi, a 68 m hill in Gifu, not Mount Kinka; access is by walking trails, not the Mount Kinka Ropeway. The summit holds a stone marker and surviving earthworks and moat traces. Parts of the hill were quarried in 1964, so the terrain differs from the original castle mound.

Sagiyama Castle was built as a residence rather than a defensive fortress, so its low 68-metre hilltop mattered little. In 1964, quarrying for fill material for the Tōkaidō Shinkansen and the Meishin Expressway cut away part of Mount Sagi; workers then found stones interpreted as the castle's foundation stones.