横須賀藩
During the Boshin War of the Meiji Restoration, Tadaatsu's retainers were divided as to whether or not the domain should continue to support the shogunate, or join forces with the Satchō Alliance in support of the new imperial government. Thanks to the persuasion of Yaso Tomiho and Aoyama Zen'ichirō, the pro-shogunate elements in Yokosuka dropped their objections, and the Yokosuka Domain peacefully submitted to the Imperial army. As a gesture of loyalty, Yokosuka Domain contributed forces to assisted the new government in its suppression of remaining pro-Tokugawa partisans in northern Japan. In 1868, due to Tokugawa Iesato's entry into the Tōkaidō region as "daimyō" of the newly created Sunpu Domain, the Nishio clan was transferred to the newly-created Hanabusa Domain, in Awa Province with the same nominal "kokudaka". Tadaatsu ruled Hanabusa as "daimyō" until 1869, when he was made "han chiji" (imperial governor). He finally left Hanabusa after the abolition of the domains in 1871, and relocated to Tokyo. He was created a viscount under the "kazoku" peerage system in 1884.