Sonobe Castle served as the administrative headquarters of the Sonobe Domain during the Edo period and was formally constructed in the Meiji era as "Japan's last castle." Today, it functions as the gate to Sonobe High School, while the castle grounds are enjoyed as a park. The reconstructed keep offers panoramic views of the townscape and surrounding mountains, making it a symbolic spot in Sonobe where visitors can also enjoy seasonal scenery like cherry blossoms and autumn foliage.