Niwa Nagahiro
Viscount was a Bakumatsu period Japanese samurai, and the 11th (and final) "daimyō" of Nihonmatsu Domain in the Tōhoku region of Japan. He was the 12th hereditary chieftain of the Niwa clan. Nagahiro was the 9th son of Uesugi Narinori of Yonezawa Domain; his mother was a daughter of Matsudaira Yorihiro of Takamatsu Domain. He was married to the eldest daughter of Niwa Nagakuni. Following the defeat of Nihonmatsu Domain during the Boshin War in 1868, Nagakuni was placed under house arrest in Tokyo by the new Meiji government, which also ordered him to retire. Nagakuni formally adopted  his son-in-law, Nagahiro who then became "daimyō", with Nihonmatsu reduced to 50,000 "koku" in its "kokudaka" (half of what it had previously held). When the post of "daimyō" was abolished, Nagahiro remained as Imperial governor of Nihonmatsu until the abolition of the han system. In 1884, with the creation of the "kazoku" peerage system, he received the peerage title of "shishaku" (viscount). He died in 1886 and his birth brother Nagayasu (Uesugi Narinori's 11th son) became the 13th chieftain of the Niwa clan.