The 3 level donjon of Hirosaki-jo seems disproportionately small when compared to the huge estate encompassed by the castle today. Hirosaki-jo was originally built with a 5 level donjon which was struck by lightning and burned to the ground in 1627.The donjon was not rebuilt until 1810.

The new 3 level donjon is built atop the inner moat using the stone wall as the palisade for the donjon. Originally it was also connected to a section of yagura along the top of this moat. The yagura, however, no longer exists and the donjon stands alone. Hirosaki-jo has the only extant donjon to the east of Matsumoto-jo (Nagano prefecture) making it a historical treasure of the Tohoku region.

Hirosaki-jo is famous throughout Japan for the more than 5000 cherry trees that fill its grounds today. Every spring when the trees are in bloom thousands of visitors flock to the grounds to partake in one of Japan's finest Cherry Blossom Festivals.