Miharu Domain (三春藩 Miharu-han?) was a minor feudal domain under the Tokugawa shogunate of Edo period Japan. It was based at Miharu Castle in southern Mutsu Province in what is now part of modern-day Miharu, Fukushima. It was ruled for most of its history by the Akita clan.
In the Sengoku period, the area around Miharu was controlled by the Tamura clan. Dispossessed by Toyotomi Hideyoshi, the area became part of the holdings of Gamō Ujisato of Aizu. Following the establishment of the Tokugawa shogunate, the Gamo were relocated to Iyo Province in Shikoku, and Aizu was given to Katō Yoshiaki, who split off the Miharu area as a separate 30,000 koku domain for his younger son Katō Akitoki in 1627. However, due to mismanagement, the peasants in the domain rose in revolt the following year, and the Kato clan was replaced by Matsushita Nagatsuna from Nihonmatsu Domain in 1628. He was in turn demoted in 1644 to hatamoto status, and Miharu Domain was reassigned to Akita Toshisue, formerly of Shishido Domain from Hitachi Province. The Akita clan continued to rule Miharu until the Meiji Restoration. At the time of the Restoration, the 11th daimyō, Akita Akisue was still underage. The domain joined the Ōuetsu Reppan Dōmei during the Boshin War. However, when ordered to dispatch forces to Shōnai Domain on April 1, 1868, Miharu Domain refused, citing its small size and military weakness. On July 26, 1868, through the intercession of Kōno Hironaka, a local samurai in the service of the imperial forces, Miharu Domain switched sides to the Satchō Alliance. This defection caught the defenders of Nihonmatsu Domain and Sendai Domain by surprise and hastened the ending of the war. Akita Akisue remained a domain governor until the abolition of the han system in July 1871. The domain had a total population of 17,034 men and 16,156 women in 7252 households, of which 904 households were classified as samurai, per a census in 1869.