Morioka Domain (盛岡藩 Morioka han?) was a han or feudal domain. It corresponded in the middle and northern parts of modern Iwate Prefecture and the eastern part of modern Aomori Prefecture. It is sometimes colloquially called Nanbu Domain (南部藩 Nanbu han?). Its income was 100,000 (koku). The Morioka domain was a member of the Ōuetsu Reppan Dōmei in 1868, and its troops fought in the Boshin War.
The Nanbu clan sided with Tokugawa Ieyasu's Eastern Army during the Battle of Sekigahara. In the wake of Ieyasu's victory, the Nanbu clan was confirmed in its lordship of the Morioka Domain (盛岡藩 Morioka-han?) (also known as the Nanbu Domain (南部藩 Nanbu-han?)). The income rating was placed at 100,000 koku, but later in the Edo era, Morioka was given the political ranking of a domain twice its size. The Nanbu clan remained here for the entirety of the Edo Period, surviving until the Meiji Restoration. Over the course of the Edo period, two new branches of the Nanbu clan were founded. One of them was granted the fief of Hachinohe, and the other one was granted the fief of Shichinohe.