The area around Iida had been ruled during the
Sengoku period by
Akiyama Nobutomo, a retainer of
Takeda Shingen. After the destruction of the
Takeda clan, the lands came under the control of
Tokugawa Ieyasu and were ruled by Suganuma Sadatoshi, followed by Mori Hideyori, and
Kyōgoku Takatomo. Following the
Battle of Sekigahara and the establishment of the
Tokugawa shogunate, Ogasawara Hidemasa was relocated to Iida from
Koga Domain in
Shimōsa Province and made
daimyō with Iida Domain, a 50,000
koku holding in Shinano Province. After his transfer to
Matsumoto Domain in 1613, the territory reverted to
tenryō status ruled directly by the shogunate until 1617, when it was reassigned to Wakizaka Yasumoto, formerly of
Ōzu Domain in
Iyo Province. His son, Wakizaka Yasumoto followed, reducing the domain by 2,000
koku with a gift to one of his uncles. He was transferred to
Tatsuno Domain in
Harima Province in 1672, where his descendants resided to the
Meiji restoration. The Wakizawa were replaced by a junior branch of the
Hori clan and the holdings of the domain were reduced to 20,000
koku. The domain's finances were never in good condition, and the situation continued to deteriorate over the years leading to widespread rioting in 1762 and in 1809. The 10th daimyō, Hori Chikashige was a close supporter of
Mizuno Tadakuni and held important posts within the Shogunal government, including
rōjū. the domain as increased to 27,000
koku, but was dropped to 17,000
koku on the failure of the
Tenpō Reforms and subsequent backlash. During the
Bakumatsu period, the domain lost another 2,000
koku for failing to stop passage of anti-government forces through its territory during the
Mito rebellion. During the
Boshin War, the domain supported the imperial side. In July 1871, with the
abolition of the han system, Iida Domain briefly became Iida Prefecture, and was later merged into the newly created
Nagano Prefecture. Under the new
Meiji government, Hori Chikahiro, the last daimyō of Iida Domain was given the
kazoku peerage title of
shishaku (
viscount). ==Bakumatsu period holdings==