April 1, 1906: Part of Tōbui Village in the former Tōbui District incorporated into Ōtsu Village. Part of Tabikorai Village,
Nakagawa District was also incorporated into Ōtsu Village.
April 1, 1955: Ōtsu Village split up among
Taiki Town,
Hiroo District,
Toyokoro Village (now Town), Nakagawa District, and Urahoro.