Iga Ueno Castle (伊賀上野城 iga ueno-jō), also known as Ueno Castle and Hakuho Castle, is a Japanese castle located in Iga, Mie Prefecture, Japan.
Construction on Iga Ueno Castle began in 1585 by the command of Takigawa Katsutoshi. However, the honmaru, or innermost bailey, as well as the tenshu, or donjon, upon which the modern reconstruction was based were built by Katsutoshi's successor, Tsutsui Sadatsugu. Sadatsugu was then succeeded by Tōdō Takatora. Takatora renovated the honmaru, giving it 30 meter (33 yard) high walls. This meant that the walls of the honmaru of Iga Ueno Castle were the tallest of any castle in Japan, a record that still holds. After the threat of rebellion passed, the castle was not seen as important as it once did. As a result, the tenshu was not re-built after it was destroyed by high winds in 1612.
In 1935, the tenshu of Iga Ueno Castle was re-constructed out of wood. It houses a museum which holds a collection of artifacts relating to the area's history. Most other parts of the castle lie in ruins, though the towering honmaru walls still stand. The castle is now a National Historic Site and preserved in Ueno Park. Parts of the Akira Kurosawa movie Kagemusha were filmed at Iga Ueno Castle.
Immediately alongside the castle is the main field where the ninja trained. By passing through it, the visitor comes to the Iga-ryū Ninja Museum which features a model village and a museum of ninja history and displays.