Battle of Aizu
In 1717, Iiyama Domain was awarded to a cadet branch of the Honda clan, under whose control it remained until the Meiji Restoration. During the Boshin War, the domain was invaded by pro-Tokugawa forces from Takada Domain, who set fire to the castle town. The domain subsequently supported the imperial armies at the Battle of Hokuetsu and Battle of Aizu. In July 1871, with the abolition of the han system, Iiyama Domain briefly became Iiyama Prefecture, and was merged into the newly created Nagano Prefecture.