Alliance of Ōuetsu Domains
  • 奥羽越列藩同盟 (Japanese)
  • Ōuetsu reppan dōmei
1868–1868
Centered, rounded black pentagram on a white square
Flag
HeadquartersShiroishi, Sendai Domain, Mutsu Province
Membership31 domains (han)
Ezo
Leaders
• Alliance leader
(nominal head)
Prince Rinnōji
• Governor-general
(de facto head)
Historical eraBakumatsu (Boshin War)
27 January 1868
• Established
25 June 1868
6 October 1868
7 November 1868
• Disestablished
November 1868
Today part of

The О̄uetsu Reppan Dо̄mei (奥羽越列藩同盟, Alliance of О̄uetsu domains), also known in English as the Northern Alliance, was a coalition formed by Japanese feudal domains during the Boshin War in 1868. The term Ōuetsu is derived from the abbreviations for the three provinces in which almost all of the member domains were located: Mutsu (Ō), Dewa (U), and Echigo (Etsu). The alliance was both military and political in nature, and was primarily established to combat the newly restored imperial government.