上野国
Tago District was the name of one of the ancient districts of Kōzuke Province, mentioned in the "Shoku Nihongi" of 711 AD. Modern Tago District was created on December 7, 1878 with the reorganization of Gunma Prefecture into districts. It included 19 villages, which were formerly part of the "tenryō" holdings in Kōzuke Province administered directly by the Tokugawa shogunate, seven villages that were part of the holdings of Yoshii Domain and three villages which were part of the holdings of Obama Domain. With the establishment of the municipalities system on April 1, 1889 the area was organized as one town (Yoshii) and three villages.