Sunpu Castle is one of the largest outline-style castles in Japan, surrounded by three moats and earthworks: Honmaru, Ninomaru, and Sannomaru. The castle tower was one of the largest in the history of the castle, measuring approximately 55m x 48m at the top of the stone wall.

Currently there is no keep. Surrounding area is Sunpu Castle Park. There is a Japanese garden such as Momijiyama Garden.

There is no parking lot, so please use the parking lot in front of the Civic Cultural Center (charges apply).