The Kasugayama Castle Site Story Museum is a historical museum and guidance facility at the foot of the Kasugayama Castle Site. Exhibits at the museum are focused on the former castle as well as the life of its most famous lord, Uesugi Kenshin (1530–1578).

At the center of the exhibition is a short documentary film that explains the life of Kenshin and his significance in Japanese history and the Joetsu area. The video also explores his long-held rivalry with Takeda Shingen (1521–1573) and the Battles of Kawanakajima fought between the two.

Items displayed in the museum include artist renderings of the castle’s layout during and after Kenshin’s residence there, as well as medieval artifacts unearthed at the castle site. There is also a replica folding screen painting depicting one of the Kawanakajima battles.

The area surrounding the museum is a historical site and encompasses restored dry moats, pathways, and topography from Uesugi’s time. Water irises planted in the moats bloom early in summer. The grounds, known as the Kasugayama Castle Historical Site Square, are where the Battles of Kawanakajima reenactments take place during the annual Lord Kenshin Festival in August.

A 20-minute walk across the grounds from the Kasugayama Castle Site Story Museum leads to the Joetsu City Archaeological Center. Together, the two museums provide thorough insight into the medieval history of Joetsu.