was a feudal domain under the Tokugawa shogunate of Edo period Japan, located in southern Mutsu Province in what is now part of the modern-day city of Iwaki, Fukushima.
In 1622, Torii Tadamasa, daimyà  of Iwakitaira Domain was transferred to Yamagata Domain, and his place was taken by Naità  Masanaga. Masanaga transferred 20,000 koku of his 70,000 koku domain to his eldest son, Naità  Tadaoki who established a separate household. On Masanaga's death in 1634, Tadaoki inherited Iwakitaira Domain and turned his 20,000 koku holding over to his brother, Naità  Masaharu, who received official confirmation as a daimyà Â. This marked the start of Izumi Domain. His son, Naità  Masachika ruled from 1646âÂÂ1696, and also served as wakadoshiyori from 1690âÂÂ1696. His son, Naità  Masamori was transferred to Annaka Domain in 1702.
Izumi Domain was then assigned to Itakura Shigeatsu, with a reduction in revenues to 15,000 koku. His son, Itakura Katsukiyo served as rà Âjà « and traded places with Honda Tadayuki of Sagara Domain in 1746. The Honda clan continued to rule Izumi domain through the remainder of the Edo period. Tadayuki's son, Honda Tadakazu caught the eye of rà Âjà « Matsudaira Sadanari after successfully reforming the domain's finances, and was promoted to wakadoshiyori and sobayonin, where he played an important role in the Kansei Reforms. As a reward for his efforts, his revenues were increased by 5000 koku. The 5th daimyà  of Izumi, Honda Tadanori established the domain's academy in an effort to modernize the domain in the Bakumatsu period. Honda Tadatoshi served as jisha-bugyà  and led the domain in support of the Tokugawa during the Boshin War. Following the Meiji restoration, he was punished for his support of the à Âuetsu Reppan Dà Âmei by a reduction in income of 2000 koku, and was forced to resign in favor of his adopted son Honda Tadanobu, who served as imperial governor until the abolition of the han system in 1871.
As with most domains in the han system, Izumi Domain consisted of several discontinuous territories calculated to provide the assigned kokudaka, based on periodic cadastral surveys and projected agricultural yields.
was the 3rd daimyà  of Sagara Domain in Tà Âtà Âmi Province and the first Honda daimyà  of Izumi Domain in Mutsu Province. His wife was a daughter of Matura Atsunobu of Hirado Domain. His courtesy title was Etchà «-no-kami and he held lower 5th court rank. He was the third son of Honda Tadanao, daimyà  of Yamato-Kà Âriyama Domain and was posthumously adopted to succeed Tadanao's elder brother Honda Tadamichi as daimyà  of Sagara in 1721. In 1746, the Tokugawa shogunate relocated the clan to Izumi Domain in southern Mutsu Province. In 1754, he retired in favor of his son, Honda Tadakazu. He died in 1773. His grave is at the temple of Rinshà Â-in in Bunkyà Â-ku, Tokyo.
was the 2nd Honda daimyà  of Izumi Domain. He was the eldest son of Honda Tadayuki and was born at the domain's residence in Edo. His wife was a daughter of Matsura Sanenobu of Hirado Domain. In 1754, on the retirement of his father, he became daimyà Â. In 1787, he was promoted to wakadoshiyori within the shogunate administration, and sobayà Ânin the following year. In 1790, his position rose to rà Âjà «-kaku, and together with Matsudaira Sadanobu and Matsudaira Nobuakira, he is regarded as one of the central figures of the Kansei period. In 1790, the kokudaka of the domain was also increased by 5000 koku and he received permission to be styled as âÂÂcastellanâÂÂ, even though the domain did not have a castle. He was a noted scholar of economics, and a proponent of the Shingaku movement. he is noted for establishing grain stores in each village as insurance against famine, and for banning abortion in his domain. He was instrumental to the shogunate's Kansei Reforms and also strongly pushed for increasing Japan's defences against the southward expansion of the Russian Empire, which threatened Ezo. He resigned his posts in 1798, and retired as daimyà  in 1800 and died in 1812.
was the 3rd Honda daimyà  of Izumi Domain. He was the older brother of Honda Tadakazu, but as his mother was a concubine, he was bypassed in the succession by his legitimate younger brother, Honda Tadao. However, Tadao was disinherited in 1785, and Tadashige became daimyà  on the retirement on Honda Tadakazu in 1800. His wife was a daughter of Itakura Katsutoshi of Annaka Domain. He continued the fiscal policies of his father. He retired in 1815, and died in 1832.
was the 4th daimyà  of Izumi Domain. He was the eldest son of Honda Tadashige, and became daimyà  in 1815 on the retirement of his father. His wife was a daughter of Yanagihara Masaatsu of Takada Domain. In 1836, he retired, turning the domain over to his 3rd son, Honda Tadanori. He died in 1839, and his grave is at the temple of Kà Âfuku-ji in Mukojima, Sumida, Tokyo.
was the 5th daimyà  of Izumi Domain, He was the third son of Honda Tadatomo, and his wife was a daughter of Yanagisawa Yasuhiro of Yamato-Kà Âriyama Domain. He became daimyà  on the retirement of his father in 1836. He built the han school. He served as a wakadoshiyori from 1841âÂÂ1860 under Shà Âgun Tokugawa Ieyoshi. He died in Edo in 1860 at age 43 without heir.
was the 6th daimyà  of Izumi Domain. He was the 4th son of Honda Tadatomo. His wife was a daughter of Hori Naotada of Suzaka Domain. He was posthumously adopted on the death of his older brother, Honda Tadanori in 1860, and was received in formal audience by Shà Âgun Tokugawa Ieshige. In 1863, he became jisha-bugyà  and the same year was also appointed sà Âshaban. In 1864, he advanced to the post of wakadoshiyori, but was dismissed only five months later. In 1866, he again became wakadoshiyori, but again resigned after ten months. In 1868, with the start of the Boshin War, he favored the imperial cause, but was pressured into joining the pro-Tokugawa à Âuetsu Reppan Dà Âmei instead. As a result, the domain was invaded by the forces of the Satchà  Alliance and Izumi jinâÂÂya was burned during the Battle of Iwaki. Tadatoshi was forced to flee to Sendai. A few months later he surrendered to the Meiji government and was placed under house arrest, with the domain reduced in kokudaka by 2000 koku He was released from house arrest]in 1870 and his court rank restored. He died in 1883 and his grave is at the temple of Kà Âfuku-ji in Mukojima, Sumida, Tokyo.
was the 7th and final daimyà  of Izumi Domain. As his predecessor, Honda Tadatoshi had been forced into retirement by the Meiji government over his involvement in the Boshin War. He was selected as heir by the Honda clan in 1868. From 1869, he became imperial governor until the abolition of the han system in 1871. He died in 1903, and his grave is at the temple of Kà Âfuku-ji in Mukojima, Sumida, Tokyo.